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This car has been running pretty good for a while now, i went down the road, and as i was driving it acted like the key got flipped over. The car will turn over but acts like the key is off. Still sounds like it is getting good compression though! Please help
Also i had a friend turn my key as i had my ear to the open gas lid, and i didnt hear any kind of fuel pump kicking on or off…not sure if that means its the pump for sure though, just let me know what you think, thanks
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Are you getting spark? Does this car have a timing belt… if so you may want to check it/ensure the valves are moving… also check all your fuses… a fuel pressure test may be necessary.. maybe spray in some starting fluid…
Eric has a step by step guide in the main screen for crank no start diagnosis…
When i turn the key i cant hear the fuel pump kicking, so that may be the isuue, ill respond after all tests
Ok, i just went out there, i took the intake hose off, and hit it with some starting fluid, and tried to crank it…and it acted like it wanted to start up there for its most likely the pump rite?
Also when it did run the other day i noticed a small lump in the idle, it wasnt so bad to where the gauge moved but i could tell just by the sound of the car…sounded like a small cam thump…or a miss
If you suspect the pump you should really check the fuel pressure. With no starts you need to verify what you have and what you don’t have. This means you need to check and verify, spark, fuel, and engine mechanical. Listing for at the fuel pump is not likely to cut it. More info in this article.
http://www.ericthecarguy.com/faq/solving-automotive-no-start-problems
First off, what year 100 is it? And what engine is in it? 5 cylinder?
In any case most those cars used a Bosch K-Jet, or a variant of. Also knowen as CIS. In any crank, no start situation listing and verifying the pumps runs is first. Secondly check the cold start injector, the sensor and the electronics for it. If it doesn’t spray you could turn the car over for a decade and it wont fire.
Easy to do, remove it from the intake manifold, leaving the fuel line and electrics connected. Drop it into a jar or cup. Key on the car. If it doesn’t spray with key on or first crank you have found the root of the usual problem.
From there I like to connect 12v from the battery directly to the injector to see if it sprays then. If that works more than likely the thermo temp switch on one of the coolant flanges is dead or a wire connection is gone.
The car is really pissing me off at this point, i took the fuel line off of the filter under the hood, and turned the key over, and it does pump, but very wesk! also i pulled the sending unit off the tank, and it looks like something about the size of a fuel pump is missing un the cap…line there is a place for another one or something…please keep the comments coming, and ill keep working and doing all that you all say to do! I have sprayed the intake with some starting fluid, and it will just kick a tiny but, but not actually start up…therefor the car does have spark (fire)…i have also been experencing that the interior of the car smells like gas…not actually in the fabric but in the air…please keep the suggestions coming so i can get my baby running again…..again the car was running just fine, and i went to pull up a very small hill, and it just 100% died out without warning, or bogging at all…
Still need to know the year and engine size! And if its a Quattro or not. Some of those cars used a single in tank set up, some used a duel pump set up.
You said it looks like there should be a pump on the sending unit also. Is there a wire connection on the tank side of the sending unit? Did you look in the fuel tank for the pump? I have seen hoses rot enough that they break and the pump falls out. When that happens no fuel gets transferred to the main pump and the car shuts off really quickly.
Fuel systems on those cars look complicated but they’re not. Just archaic by todays standards. This next stuff might be a bit pre mature until we know the exact vehicle you have but its good knowledge on the KE-Jet system.
First off.
You need to measure the fuel pressure. KE-Jet fuel systems run quite the pressure. Too low and nothing happens. If you jumper the relay spot for the fuel pump and let it run you should have 78ish psi. Its not an easy one to test and you do need a fancy two hose fuel pressure tester. Before you go that far to test pressure fuel follows this path:
tank – pump – fuel accumulator – filter – primary pressure regulator, then into the fuel distributer. Inspect the fuel lines too for any leaks, or crushed spots. You said you can smell gas…..
Both a bad fuel accumulator, and bad filter will cause low fuel pressure. In the same breath just pulling the hose off and letting it spray gives you no indication of pressure. If its a dribble then there is something wrong for sure. I would disconnect the hose right off the fuel pump and see how much fuel it can produce. If its just a dribble I’d suspect that. If its spraying good Id be questioning the fuel accumulator. Its job is to absorb pulses from the fuel pump as well as hold residual pressure in the system. If the diaphram inside is dead it can block fuel flow. It should be right next to the pump.
Work in this order:
Does pump spray or dribble when disconnected from accumulator.
Does fuel spray or dribble when accumulator outlet hose disconnected.Ideally you need a Bentley manual. There isn’t a better book.
the car is a 1994 audi 100 with a v6 in it, and a 5 sped trans if fit matters…With the hose off the fuel filter under the hood and key turned to the on position, gas does come out! but its no 70-80 psi!! i can place my finger over the hose and stop the flow all together without much effort at all..need this car to get me to my army base every wednesday for training…and at this rate im not making it…Thanks so much for the time and responses!!! the car seems to have fire because it will kick and fire with some startting fluid…mot or turns over free without crunching, or cracking etc sounds 100% normal but no start of corse
Try to avoid making assumptions and do as much testing as you can before you remove or replace parts. Audi parts are expensive after all. Just some basic tests like checking the actual fuel psi can tell you a lot. We are not wizards that can provide you with the magic bullet that will solve your problem. We solve things by testing and verifying, not guessing. If you can, do some basic diagnostic work and you’ll have a much easier time of it.
Good luck and keep us posted.
Not many left with the V6 in it. The V6 used Motronic so ignor everything I wrote based on the 5 cylinder engine. I appologize for assuming it had the 5 in it.
Motronic uses much lower pressure, 45ish psi. It also uses an in tank and main pump. Have a look in the fuel tank to see if one broke out of the sending unit. Without the in tank pump the main pump wont work.
If you end up changing the pump change the filter. In tank pumps are usually around $75. The filter is worth $10. Hopfully thats all it is. When in tank pumps die they have a habbit of stalling the car, and can burn up the main pump from it running dry.
The only issue, is that im not a big time mechanic, and i dont have all the cool tools and gadgets to do these tests…ill take a very close look at it this weekend, and come back to let you all know whats going on…thanks
OK THANKS!!! so there should be one attached to the sending unit, and inside the tank, or one on the unit, and one completely separate…
Make sure you look in the tank to see if its rolling in the bottom. If its not there, it didn’t need it, or didn’t come with one. In those years there was a fair bit of variation with things like that between model to model and or things get “upgraded” to the better way used on other models. Like I mentioned earlier in the thread, Its common on older VWs to have the twin pump set up removed and a single pump used.
If you plan on keeping the car – and you should, I’ve seen those cars pull jeeps out of snowy ditches – buy the Bentley manual for it. They arent cheap. Hands down its the best documentation you can buy. It will walk you through, easy to understand trouble shooting for every part of the car. From things as easy and changing the front brake pads, all the way to setting the cam timing. I keep a shelf full of them. Amazon often has used ones for great price.
Another thing to consider too is get involved on an Audi owners forum. There’s a million for VW and I can only imagine there is a tonne for Audi owners too. Most of them have deep data bases and or entire forum category’s dedicated to your exact car. Forums are not a great way to learn to be a mechanic in no stretch but they are great at learning how things work and how to trouble shoot things specific to the car.
Edit add on:
Also, Bosch did a really great job of providing specific manuals for the fuel management systems to mechanics who worked on it. You can find them online in Pdf form all over the place.Hopefully you get your Audi going well again very soon!
ok, i have opened the tank up today, and felt around…and dont think there is another in the tank, other then the one at the bottom of the tank…thats suspost to be there…so next step from there…the pump will push some gas to the front of the car but with barely any pressure…(NO WAY TO TEST PSI)
Is yours a Quattro or 2wd? I did a quick check with a friend at a dealer and the tank/pump set up in a 100 is identical to a 90. Thankfully I’ve worked on many cars using the 90 platform. Your car came stock with a single pump in the tank. That’s it. It mounts in the sending unit, and the wires connect from the sending unit to the pump via 2 nuts / ring connectors on its top. Standard for any VW/Audi.
If you’re getting nil for pressure from it replace it. But be sure its dead. They aren’t cheap!
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