Another QV won't start thread

I have a strange starting issue with my '85 QV. The car starts fine when it has not been driven for a while and is completely cold. When I drive it to full operating temperature, turn it off, and then start it again soon afterward (like when I get gas), it still starts fine. However, when I let it sit for longer, like an hour, it won't start. It will just crank and crank and crank, but won't fire up. In such cases, I need to let the car sit for a long time, like another hour or more, and then it will start again like nothing was wrong. Last time I had this issue, the engine was relatively cool -- water and oil temps didn't even register on the gauges. So, it's not a matter of the engine being hot.

Anyone experienced anything like this with their car? Any suggestions on a fix?

 

There is a fuel accumulator along the fuel pump and filter. Any idea about it's age?
Could be that the pressure in your system is too low after shutting off,
cheers
braq

 

By chance have you upgraded the fuse blocks?
I used to have a very similar issue with my 84 GTB QV. Could walk out into the garage and start immediately. Let it run for 20 minutes, shut it down and could not get it started for another 30/50 minutes. Installed a set of Birdman fuse blocks and never had another issue.

 

I don't know, but I agree that this could be the culprit. It just seems strange that the car will start after a few minutes but not after an hour.

Interesting. Surprised this would be a factor.

 

Yep, I could actually try to start the car for 20 solid minutes and could not even get it to fire once. Let it sit for an hour, turn the key and it would start immediately. One of the members here suggested I change out the fuse blocks and sure enough cured the issue. Also cleared a few other little electrical gremlins the car had from time to time. Maybe do a search of Birdman fuse blocks and see what other members have said.

 

Okay, I'll check the fuel pump/lines first and, if they look okay, try the fuse blocks.

 

The accumulator has diaphragm
It's holding pressure briefly but bleeds off hence the long no start
there are several good threads on replacement
be careful with the metal line between the pump and the accumulator
Change the fuel filter while you're right there

 

I don't think the problem is the accumulator, but an easy test is to remove the hose that goes back into the fuel tank. If fuel spills out there, the accumulator is bad. EU models don't have that hose, and will just leak fuel on the ground when the accumulator fails.

The problem here is a lack of fuel, or lack of spark. Pick up a spare spark plug, then when the problem shows up, pull one of the extenders and attach your spare plug. Lay the plug on a grounded metal surface, then have someone crank the engine while you watch for spark.

To test for fuel, turn the ignition key to the run position, pull the air filter housing, then press down on the air metering vane. As soon as you press on the air vane, you should hear the fuel pump energizing. There should be pressure against your finger, this is the primary fuel pressure. If you press down hard on the vane, you can hear the injectors spraying. It's a high pitched screaching noise coming from the injectors. Of course this will flood the engine temporarily, but you will know if the fuel injection system is working or not.

 

If the accumulator is not doing its job, you are losing the pressure in the fuel lines when the engine is stopped. When you 1st start the car the fuel lines are cold and the pump will give you sufficient pressure to supply the injectors and it starts.
When you stop the engine the fuel pressure in the lines should be maintained by the accumulator, but if this is no good then the pressure drops, the fuel in the lines near the engine is hot- the lack of pressure allows vapour to come out of the liquid and you cannot get enough pressure in the fuel lines on the hot start.
Easy to change

 

I have an 1983 QV with the exact same hot start issue..... It's an all original car (except for cam belts) with 60,000 miles. I've had the issue for several years, have some time on my hands now, and looking forward to hear if you have been able to isolate it ????

 

Changing the accumulator is a quick and cheap diy job, so well worth trying to see if it cures your problem

 

if its not the accumulator - then its going to be electric... couple of points


1. frequency valve under the rear right side trunk - fuse could be bad in the relay... doubt it but possible. it gets warm in there and it expands.

2. Faulty connector - the plastic connectors start to overhead and develop cracks in the solder .... thre are several behind the fuse block, and two under the passenger foot board.

3. Faulty Start valve.. but doubt it..

4. Fuel pump fuse / relay. this is a notorious weak spot for the QV - mine used to burn up every 2 years...

5. Fuse block ... it happens, replacing the fuse bock with a newer ( Birdman ) or 328 one can help... but its a lot of work.

 

Swap the fuel pump relay with another one with the same specs in the fuse box. There are several of the same spec (seat belt buzzer). This cured my 308 starting issues. Napa ar230 relay for my 1980 308.

 

You folks have sparked my interest in getting this resolved. I will first try swapping the fuel pump relay, if that doesn't work I'll order up a Bosch #438170004 (accumulator).

This forum has helped me resolve several issues in the past, thanks for all the thoughts and troubleshooting tips

 

Sorry, have to disagree with the fuse box being alot of work to change out. Takes about an hour to do both blocks and have the car running.

 

If it is starting ok from cold then i would think the fuel pump is working fine, other wise you would have a misfire if lack of pressure, more like accumulator if problems on a hot restart