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Problem first. As of the past week and a half, both my friend’s car and my own have been sputtering under load when it reached operating temperature (when it sputters badly, the low oil pressure light comes on). As of the past couple days, sometimes both vehicles will stall. Typically I can get to a safe spot to pull over if I have a smooth road and keep the RPMs under 1900. As of today, it’s getting harder and harder to get to a safe spot to pull over due to it stalling sooner. My friend switched from 5w-30 to 10w-40 and so far it has seemed to help him. Earlier today, I let my car idle with some Seafoam and then I changed the oil from 5w-30 to 10w-30 but my problem still persists. We both have new plugs (mine are NGK coppers with 7?? miles on them). I also have new wires and a fuel filter. I have checked a couple of my plugs and they seem to look great with no fouling (I plan to pull them all tomorrow). I have 38 psi at my rails on idle when cold starting. My wires have good resistance. My battery terminals are on snug. Oil and transmission fluid are at ideal levels (and checked a couple times a week to ensure good levels). I also poured some Seafoam in with the fuel in case the fuel was compromised.
So my plans for tomorrow are to pull all the plugs, check gap, and clean if necessary.
I was wondering if anyone else had this kind of problem or if they had any suggestions. My research has brought me to suspect the fuel pump (replaced about 22 months ago), Ignition module, Crankshaft Position sensor, or coil packs. I know a while back, my car threw a high/low voltage to fuel pump. I checked the relay and it was fine. I had the same voltage from the fuse/relay box (where the positive cable hooks up) all the way to the fuel pump which leads me to want to rule it out, but I won’t until I know for sure. Recently (before my recent plug and wire change), I had E3 plugs in and they had nearly all failed with 11,000 miles on them. I also do have a high output alternator rated at 220 amps (been on for 17 months) for my sound system (I also run an Optima red top battery).
Now for some info on my car:
1995 Pontiac Grand Prix SE w/ 3.1 SFI 60* V6 with 4T60-E
Current milage 174,???
Oil change at 174,??? (less than 30 miles on oil change so far)
Oil change at 173,???
Spark plugs, wires, and fuel filter at 173,???
Timing chain, coolant flush, and oil change (including all necessary gaskets) at 172,???
Complete upper gasket including head gaskets and all new bolts at 169,??? (Head gasket was cracked but only driven about 60 miles with little contamination) (compression test was done and I had 170-175 psi on all cylinder on a dry test.
Transmission flushed at 162,7???
Fuel pump, sending unit, filter, fuel pump relay, and strainer at 163,???
ALL fluids look, smell, and feel fine. I typically change the oil and filter every 2,200-2,800 miles.
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No luck yet on anything yet. I replaced a few of the cheaper parts to help me either rule out or figure out the problem. I replaced the oil pressure sensor/switch, engine coolant temperature sensor, and the fuel pressure regulator (smelt a strong fuel smell in the line). After doing that, my problem persists. My fuel pressure is 35-36 on idle. I have a strong feeling it’s the fuel pump. Just called my local GM dealer and they say it’s supposed to be between 40.5-47 psi. So I’m gonna end up grabbing one. But in case that isn’t the problem, let me give some more information on how it’s acting now.
Every day it seems like I can only travel a little shorter until it acts up. Instead of it’s typical response, now I’m usually fine until it gets warm and I stop at a stop sign/light. When I try to accelerate at all, it sounds like it’s only hitting on one cylinder and I slowly creep to a safe place at 1 mph. I’ve also noticed a couple times that when the pump was warm and I turned my car on (engine off) (relieved fuel pressure), I couldn’t hear my fuel pump prime or it was very faint. So, I’ll probably replace that Saturday and hope all is well from there on out.
The 95 Grand Prix has been the main vehicle in discussion. When I mention my friend’s car, it’s the 91 Honda Civic SI.
Well, I planned on hooking up a narrow band air/fuel gauge to my Grand Prix to see how the O2 is reading to help eliminate that. Upon looking, I noticed a wire that led from the lower rear of the block (probably the crankshaft position sensor) up to the primary side of the ignition module. It seems to have been the crankshaft position sensor. It was resting on a part of the header and seems to have melted a bit of the insulation (not a terrible amount). I relocated those wires. I also replaced my fuel pump. Drove around for about an hour without a hiccup. So I don’t know if it was the pump or the wires, but so far so good. Fuel pressure has varied from 36-46 (depending on load) which is better than it was. I don’t know if I fixed it for sure, but if I didn’t, then I at least postponed it for a little bit longer. Guess I’ll know in a couple weeks.
If the crank sensor wires are not routed correctly on those cars they will touch the exhaust and burn through.
[quote=”wysetech” post=69679]If the crank sensor wires are not routed correctly on those cars they will touch the exhaust and burn through.[/quote]
I’m guessing it happened when I did the head gaskets. Regardless, I did relocate the wires as best as I could without getting too close to the headers.
Other than that, 30ish miles and no problem yet. I do have to drop the tank again as it seems my floater camemust have barely come loose off the assembly. Until then I’m running with x% fuel. Haha.
So far so good. Nearly 9 days and over 200 miles. However, my sending unit is weird. When the tank is on the ground, it works fine. When it’s mounted up to the car, it doesn’t. I know there are no shorts. So, I’m going to check for wires not liking a certain position. Any Ideas?
Grounds are good. I know they are. The ground it uses is on the sending unit with a clip connector on it. Here is another example of how weird it is. All I did was loosen the bolt on the driver’s side strap all the way and it worked. I checked for pinched wires and I noticed an area where it was pinched. All the wires looked fine (none broken or cracked). I get the bolt back in and it doesn’t work (with no wires being pinched). I don’t know what is going on here. But, I may get a longer bolt with the same pitch and add a spacer between the strap and the uni-body to see if it’ll work that way. At least I know if I want to check my fuel level, all I have to do is keep my cordless impact (from Snap-on and I love it to death; huge time saver) and a 15mm socket handy. Bit of a hassle, but at least I know I can if I’m unsure of my fuel level.
Well it seems the problem is back. However, its not jerking when it acts up. It’s a lot smoother now. Like its just missing spark. I checked the wire and the loom melted a little more. So I’m going to first try and relocate it again but this time im going to add some electrical tape and check the tape every so often. If I have no luck after a while, I might buy some hose, slice it open, and put the wires inside the hose. Help keep it isolated from heat and metal. Might also replace that wiring, sensor, and connector.
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