QuestionQUESTION: my bus starts fine but will not stay running. if the gas pressure is only 25-30psi is that sufficient to run a fuel injection engine?
ANSWER: John,
This pressure is in the ball park. I would look for other problems. I would need a little more info to diagnose.
- Rick
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QUESTION: i have replaced plugs,points,condensor,distrib. cap,wires,double relay checks out,cold start checks out,egr checks out,chop sticks work the air flow fine,timing is good,valves are adjusted correctly. the van starts but will not let me accelerate or run at idle after 10 seconds then it dies.
ANSWER: John,
I double checked my bus manual, the pressure should be 35PSI, and a bit higher under load (the pressure regulator vacuum port controls this). So I have to correct my last post and would say 25-30 is too low. Here are things to check:
- Fuel tank vent clog; if the tank becomes a vacuum, this will restrict flow.
- In-tank fuel filter clog
- Main (external) fuel filter clog
- In-tank fuel pickup hose cracked near top; sucking in air
- Faulty pressure regulator
- Kinked fuel line or incorrect size (too small) fuel line.
- Less than 12VDC at the pump.
- Faulty pump
Another possibility is you have a "false air" problem, which means there is a leak somewhere in the air induction system. This will cause bad idle and stalls too. Look for loose/cracked hoses everywhere. Spray starter fluid around any suspected areas while at idle; if the RPM increases while spraying you may have found the location of the problem.
Rick
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QUESTION: rick, thanks for your help. one more question though, if the markings are off on the fly wheel, how do i re-establish the mark for future timing purposes( i cannot find the timing mark)
john
AnswerJohn,
First you need to find TDC (Top Dead Center). Of course this is for cylinder 1. One way is the remove #1 spark plug, insert a wooden dowel in the hole and observe while hand turning the crank. When the dowel is pushed out to the limit and starts to go down again, and the distributor rotor is pointing at wire #1 (this needs to be checked because each cylinder has 2 TDC positions; only 1 of these is for the POWER stroke) you are close to TDC, but this is not accurate enough yet.
To be precise, do this:
Keep turning the crank is either direction under the dowel goes down about 1 inch. Stop and pencil mark the dowel exactly where it enters the spark plug hole. Also make a fine mark on the crank pulley where it aligns with the mark on the case, maybe with a china marker (grease pencil) or whatever works. Now turn the crank in the opposite direction until the dowel comes all the way back out and continue turning in the same direction until the dowel goes back down to the same 1 inch mark. Stop and make another mark on the crank pulley at the case mark. TDC is the point exactly halfway between the 2 marks on the crank pulley. You can find this by wrapping a small piece of paper along the circumference of the pulley, transfer the 2 pulley marks to the paper, fold the paper in half so the 2 marks meet. The point of the paper fold is TDC. Transfer the paper halfway point back onto the pulley; you have finally established TDC. Once found, you should make a more permanent mark on the crank pulley with a paint marker. When you are confident this mark is good (by tuning and test driving it later), you may want to actually file a small reference notch for it.
You then need to make a mark for actual timing. If your bus has the original engine/distributor, the the mark should be for 5 degrees ATDC. This is 7mm to the left of TDC. See here:
www.aircooledvwlove.com/how-to-set-ignition-timing-on-an-air-cooled-vw/
You should also make this mark permanent later.
- Rick
