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When I put in the Hughes Engines Plenum Kit I replaced all sensors in the Intake and the TB. The TPS had been replaced sometime after I did the EGR but before I learned enough to find out about the Plenum issue so it is a bit older by a few months than the IAC, and MAP sensor. The O2 sensor, there is only one, is new in that time span as well. The guy who hooked up his Solus to see if he could check the Injector Sync showed me the O2 sensor reading going from rich to lean back and forth and said that means its good. Someone else confirmed that but it makes no sense to me as the motor should stay stable imo.
I had the intake tanked and i got one of those gallon cans of cleaner and soaked the TB in it.
I’ll have to ask about the Transmission control module.It has been suggested that the fuel pump may be the issue. I do not think the pump is it but there is an issue I think had a TSB with the wiring to the pump. It’s possible but the nature and circumstances of the issue when it occurs seems like it is something governing the power the motor makes not intermittent fuel starvation. The recent improvement at 0-40 makes this even more unlikely imo.
EDIT: if you know this vehicle has a TCM please let me know where it is. I am researching and have found some info indicating it may be the problem. I’m unable to find anything specific to the 42RH transmission so far. Some info indicates the TCM may be integral to the PCM. I wish I would have bought that Jet performance computer upgrade with scanner to change settings when I could.
Edit2: Called dealer I do not have a TCM. I spoke to a service guy (different dealer from the guys who said it was fine) he suggested exhaust restriction. I had done a vacuum test according to Eric’s instructions and it passed. He thinks Cat may be clogged and suggested removed O2 sensor and driving it to see if the problem improves or goes away. I may do that since it’s cold right now.
Edit3: I got a gauge to test fuel pressure. It is 37-40 psi. When revving it stays steady. around 39. I got a 1lb rubber hammer and smacked the Cat a few times. There is nothing inside it shaking or moving around. I did not remove the O2 Sensor.
Yeah, O2 sensors are supposed to go rich, lean, rich, lean. It is normal for them to do that. Basically the engine is trying to stay at a stoichiometric ratio aka the golden ratio or perfect air fuel ratio. There is another reason I am just drawing a blank on it and can’t find it atm on the internet. When it is oscillating it is in closed loop aka the ecm is controlling it. If it was not oscillating it would indicate it was in open loop aka warm up mode it is called open loop because the contacts for the ecm to read it are open therefore no electricity passes to the ecm. Nowadays the values are just ignored till a certain temperature but, the nomenclature stuck.
O2 Sensors can be sluggish aka lazy. This is when they are not responding with the proper frequency or amplitude. Most people do not check for this when they are doing an O2 test. They just look at the values and never graph it. A worn out catalytic converter can cause this. A worn out O2 sensor heater can cause it as well. If you can unplug them and secure them so they will not melt the connectors or rub against stuff if you unplug both it might set a code but, it should use a substitute value and you can
The exhaust restriction makes sense from the performance stand point but, it does not explain the rich smell aka fuel smell. That smell of fuel in the exhaust is that only when its cold or once it is at operating temperature?
The rich fuel smell has happened several times. I do not notice it most of the time. I don’t know what it is since its not continuous. That day I smelled it at the front of the truck with the hood open and the wind wafted the exhaust up front. I have smelled it when I started then pulled out through the exhaust as I backed out. There is no smoke except for when I did that wet compression test. It occurs as I write and have looked at a cat for dummies diag page that this thing may not be working properly even if its not full of loose stuff.
Edit: I went out to get a thermometer and it drove waaay better. It only did that RPM kickdown near fifty once that I noticed. Is is smooth and well I assume I knocked something loose on the Cat when I smacked it yesterday. The temp semsor said the Cat was 114 in front and 95-99 in back at Home despot when I got home it was 168 at the front weld and 125 behind the clamp at the back. I’m thinking that in spite of having passed the vacuum test the Cat should be replaced.
I have spoken to Midas and the guy quoted the price then put an awful lot of effort into talking me out of it. First he said that the temp was supposed to be hot in front and cooler in back. When I stated that I had read differently he went into a schpeil without acknowledging that or stating yes or no to it. I had been told the temp thing by the Radiator/muffler shop I usually use yesterday as well. They said that is how they check.
Then He started by saying “I hate it when people say “my Cat is bad” then asked me some questions and i generally described the RPM issue and how it seems like something is actively taking away power sometimes when I am trying to make power. He brought up the EGR and when I told him I had replaced it since it had a code when i bought it and the code never came back. he said “that doesn’t mean anything”?!?!?!? Then he threw a red herring at me by asking if I had “changed the transducer with the EGR. I didn’t know and I figured he was talking about the part that is attached to it out of the box but was not sure and he ran with that and started saying stuff about how vacuum should be opening an closing it a the right times and that I need to get a gauge and drive it around to watch it and compare to the specs. Sheesh! then he said “Chrysler usually sends two when you get a transducer just to be sure it works” ????!
Well I looked it up and it is the darn part that comes with it & the harness plugs into and has the plastic diaphragm and tubes coming from it back to the EGR. All is connected and there is no sign of a leak in the vacuum lines. I’m petty sure there would have been sign of it when I was spraying cleaner around the area looking for one while it was running.
What I think I understand from all that is that the Cat cannot be causing me problems if it is not totally plugged up. ????
He wants me to think the EGR may not be opening and closing at the right time. He suggests I put a gauge in the O2 hole to see that I have less then .5lbs pressure or to drive it without the sensor in to see if it runs better. He obliquely took several shots at me for “throwing parts at the problem” ie install the EGR for the code without first chasing down the whole system. I didn’t give him the satisfaction but it was pretty much plugged up and worn out when I removed it to look at maybe cleaning it that is why I replaced it.
He created just enough annoyance I am doubting myself right now. He also said something about Cat’s not ever getting plugged he said they melt from within Starting new as a honeycomb and over time wearing out and melting down. That;s a first for me. I have never ever heard that assertion before.
I have the feeling this guy was full of it and trying to take advantage of technicalities and careful wording to make money like a scumbag would.First off those cats look low for temperatures but, it would set a code for catalytic converter inefficiency.
Exhaust Gas Recirculation (EGR) works like this. You have a pipe that connects to your exhaust. It goes to an EGR Cooler where there are a bunch of small coolant pipes running through a larger pipe. The smaller pipes have space inbetween them for the exhaust to flow. The coolant cools the exhaust. Then there is an EGR Mixing valve. It controls how much exhaust gas goes into the intake. The transducer is what actuates and/or measures the roatio of the EGR Mixing valve. When you said you replaced the EGR though you meant the EGR Mixing Valve as well as the cooler.
The EGR is used to lower Nitrous Oxide aka NOx emissions and also too cool the pistons. Since the Exhaust has already been burned at least once it does not have much oxygen left. The oxygen that is left is normally in the form of NOx so by burning it again it uses the oxygen in the NOx and puts out pure Nitrogen or N2. It cools the cylinder because there is not as much oxygen, which means less fire, which in turn means less heat. This also helps lower NOx production as it only does that when cylinder temperatures hit 2500+ F during combustion.
As for the EGR Mixing valve being hung up. It is possible and does happen but, normally the motor aka transducer itself doesn’t burn out unless this is a brand problem or known issue. Normally it is the valve being full of soot and it needs to be cleaned. Sometimes the shaft will even snap. Once again these should set a code. The valve itself in most cases I have seen is a butterfly style though other styles do exist.
Catalytic converters can become plugged. This is normally the result of oil, unburnt fuel, or coolant getting into the exhaust. It is normally remedied by driving on a long road trip 4+ hrs. Though if it is really bad removing it and cleaning it as in the Eric the car guy video is wise. With you having the EGR issue it is possible that it caused it to clog and with you saying that you hit the thing and it started driving better it is worth a shot going after it. The problem though it is going to be extremely rusty and removal may be a pain. Make sure if you do this wash it in both directions and rinse it thoroughly. Allowing it to dry would also be a decent idea. I strongly suggest using dawn original formula as it works the best on grease/oil/soot.
To melt a cat normally requires an substantial amount of oil or fuel being dumped into it while it is hot. It will create a fire inside which will then feed on anything left in the exhaust gases and any particulates that may be left on the substrate. This can get so hot it lights the vehicle on fire and burns it to the ground. I have had this happen on a big rig where it was bypassing oil from the turbo. It got to 1500F before I caught it. We had to replace the DOC and DPF which is not cheap at all. At 1500F it did not melt it but, it did remove the precious metals making the DOC and DPF useless. The DOC is a cat on a diesel and the DPF is something that cars do not have atm it is used to catch particulates in the exhaust.
As for the gauge in the O2 sensors if you do that putting it in the one before the catalytic converter will let you know if exhaust is plugged though it could be a collapsed muffler as well. After the Catalytic converter will let you know if the muffler is collapsed inside. So basically you would need to do both. Subtract the one after the catalytic converter from the one in front of the catalytic converter and it will give you the amount it is restricted. As for the .5lbs I am not entirely positive of what the numbers should be.You are going to want to wait for them to cool down in between cause they will be hot. If you turn on the car the O2 sensors heat up to around 1400F so be ware.
If you remove the sensor before the cat and drive it and it drives noticeably better you may be on to something. So then you would need to put it back in and remove the one after the cat to verify the cat is the problem and not the muffler. You are going to want to wait for them to cool down in between cause they will be hot. If you turn on the car the O2 sensors heat up to around 1400F so be ware.
Your cat temperature question is answered in that video linked above.
The quickest way to cool down the exhaust is let it idle for 15 mins then shut it off put some fans blowing at it and wait 2-3 hrs. Use the temperature sensing device you got to test it before you touch it.
I normally do not think of the cat getting clogged unless the vehicle has a turbo or has had coolant coming out of the exhaust. It normally only occurs when the EGR Cooler fails and the coolant mixes with the exhaust, a turbo oil/coolant seal goes, or your crank case ventilation system becomes plugged. I do believe I told you to check your Positive Crankcase Ventilation (PVC) valve. If not it would be wise to and to also blow air in both directions of where that hooks up to make sure it is not plugged.
The temps were probably low because the first set was at the Home Despot parking lot which is less than 10 miles and it had been sitting for say 10 minutes. I did have it idling while I took the temp. Then I drove around town and on the Hwy some more maybe 10 miles more to make it warmer and when I got home that is the second set as soon as I shut it down.
IDK if there is an EGR issue. I had the code when I bought it and I removed it and replaced it. It never set a code again. I think the Midas guy wanted to do diagnostics and was trying to feel me out for what I knew. It felt real ‘used car salesman’ to me. The EGR on this model comes with the transducer as part of it. here is a ebay page the first one is what it looks like.
http://www.ebay.com/sch/items/?_nkw=DODGE+EGR+VALVE+4287782,+92-97+DAKOTA+3.9L,+94-97+RAM+1500+3.9L,+94-97+VAN+3.9L&_sacat=&_ex_kw=&_mPrRngCbx=1&_udlo=&_udhi=&_sop=12&_fpos=&_fspt=1&_sadis=&LH_CAds=&rmvSB=true
The one I removed was really plugged with soot in those holes on bottom. It seemed toasted to me.
Last night I went out and disconnected the EGR wiring cleaned both sides and put on some dielectric grease and the same with the intake air temp sensor. There were no obvious problems in the vac lines I could see. I could not find the solenoid that the Haynes manual mentions. It seems like the EGR is just one of many things in a long loop of vacuum connected items. If there is a solenoid somewhere it may be causing a problem sending in exhaust gas into the intake at the wrong time diminishing the oxygen level. I drove it some and it still has the ticking (lifter?) noise on the hill. I went up to 55 and it seems to be still wanting to drop RPMs while accelerating through 50mph. I did not notice a difference by messing with the EGR and the Intake temp sensor.
I honestly get the feeling that most of the “mechanics” in business around here are just book learning mechanics and have no knowledge of how to make motors run good if the necessary info is not in an instruction manual and that they have to go through that manual to find and fix anything. Well I suspect some of them do but it is more lucrative to pretend they don’t. I’d expect a mechanic to know some things and well this motor is known for a lot of the issues I have had. I’d have expected a mechanic who has dealt with them to say “this is a prob and these are the most common fixes to the problem”. I expected that 21 years on these things would be common knowledge in the industry.
The Midas guy shot himself in the foot by making the “they never clog they melt” claim because literally a minute earlier he had described the symptoms of a clogged Cat! People sometimes huh? (Edit: Oh yea he also tried to get the temp sensor test being the correct temps past me too!) Anyway I called another Midas about 60 miles away and the guy who answer did almost the same thing except he didn’t bother giving me the price quote for it he went right into trying to talk me into diagnostics. Must be the same franchise owner. My experience with Midas is that they are straight forward with quotes and if they believed I had to eliminate other possibilities first they say that and leave it there or provide the quote for that elimination procedure.
I’ll watch the vid. I don’t recall if the Cat is welded up front or not its definitely clamped at the rear. BTW this is an OBDI and it only has the single preCat O2 sensor. If I do that removal drive test since I do not have the bushings necessary to make any gauge fit the O2 sensor I will probably have to disconnect the pipe behind the Cat and drive with that open.Yeah I was not sure if OBD-1 or 2 because around that time is when manufacturers started applying the technology even though it wasn’t made mandatory till 1996. Some brands and vehicles were made with it in mind before that.
If you can get the O2 sensor out. Try it. Just make sure it is still hooked up and zip-tied in a secure area where the heater will not light anything on fire. This should also make it run richer. Which if there is soot back there should help burn it out. I would drive it for like 10-15mins like this. Try not to do any longer then that as that cat will get very hot. If you would rather you can just disconnect the sensor and leave it out of the pipe and see if it makes a difference this will not dump excess fuel. It will use a predetermined value in the ecm. Not sure if it will put the car in limp home mode though.
If there is a tick it is very possible it is a lifter. If you can record a video of the sound with your phone and upload it to youtube. It normally sounds like a ball bearing tapping on a metal work bench very lightly.
I just went out to try it and opened the hood to let some light on the situation. It has been suggested the exhaust may be leaking so I took and open end to get the size and it moved the nut on the front passenger side exhaust manifold stud. So I got the ratchet and in less than 1/4 turn it was snapped off. Its got toms of corrosion in the break so I;m guessing someone else started to noticed it broke and stopped before breaking it off.
That took the wind out of my sails a bit. I was looking at possibly running new pipe with new Cat back to the muffler or maybe all the way. But I still have to isolate this Cat thing to be sure about it. The other stud and two bolts are plenty tight I don’t expect a change in operation and it wasn’t leaking so much I could hear or notice it standing over the spot for a very long time while it ran.
So once I am happy with how it runs at the least I have to drill that out and replace the fasteners.
The ticking is probably the lifters but when i had the top off to do the plenum I figured it was the lack of the tensioner at the timing chain so I just did the timing chain. I may just take a break with working on it once i get it running good enough so I can take some road trips maybe hook up a trailer to see how it feels & to see how I like it. If I want to go back to using standard I may sell it then and get a different truck more suited to my needs. I will definitely do much more research on that. But at least I’ll be able to get my money back if I get this thing running right.[quote=”94newtome” post=141972]so I took and open end to get the size and it moved the nut on the front passenger side exhaust manifold stud. So I got the ratchet and in less than 1/4 turn it was snapped off. Its got toms of corrosion in the break so I;m guessing someone else started to noticed it broke and stopped before breaking it off.
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at the least I have to drill that out and replace the fasteners.
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If you completely remove the manifold you should be able to twist out the remaining part of the stud without drilling, if there is enough meat left to get a vise grips on (and a healthy dose of penetrating oil). In the future, always soak the exhaust fasteners with a good penetrating oil such as PB Blaster, and apply some torch heat, and they will usually come out without breaking (I do realize the fastener that broke on you was previously damaged, but this practice is a good one to follow anyhow). I hope you won’t have to drill it. That can be a PITA.Thanks Cap269.
I’m probably going to get myself set up in the next week to be able to leave it sit for a day or two and slather the bolts and nuts with lube and replace them all. Hopefully nothing is cracked and that stud left a bit hanging out. The break was right at the end of the threads where the flat part is so I guess it depends on how well they were sunk before putting the manifold on.Edited: I was tired and said something stupid lol. Just make sure you follow torque specs and the tightening order for them. I would pick up a paint marker if you have to do 90 degrees or what not.
No worries. I have to do some other things before I can get to this issue. The research I have done this morning shows this is common and that it may be the source of my ‘lifter noise’ issue. Hopefully it has not warped any valves which apparently is a possibility. So I won’t be able to get to this until late next week when my other rig is free for me to drive. I plan on removing both manifolds and replacing all fasteners.
I wonder if going with a more restrictive exhaust on the 94 has lead to this?If you are going to remove them replace the gaskets. They are normally one time use and normally have to be scraped clean but, have to be done carefully so as not to score the surface.
MDK22,
OK Nothing new on the headers but I did get an MT2500 off eBay.
I finally got to check the fuel sync and it was at -5 and fluctuated to -10 or more! I got it to sit at +1 and it occasionally went up to +5
I reset all the items it let me reset to relearn IAC and something else I think maybe two other things and I drove it.
It seems much different. First of all no valve or lifter noise going up the big hill near my house. It did drop the RPMs out from under me but it also responded as soon as I pressed the peddle down.
It drove better, accelerated better and it did not feel like that out of round thing was happening. I still think I need to do the CAT I will probably replace the Y pipe too and hopefully the muffler is not full of CAT pieces.
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