I'm looking at purchasing an 89 turbo that's been sitting up for a while. I've been reading rennlist, pelican, Clark's, etc for weeks now and I'm pretty familiar with what's ahead of me, but I have some questions about the fuel system. The owner (who's opinion I trust) thinks it should only need a new battery and a fuel pump to get it cranked over.

1. I know the relays can go bad. Does the relay only affect power to the pump or is it somehow linked into ignition and spark as well?

2. If the fuel pump is just gummed up, can it be cleaned or is it just plain better to get a new pump?

Although my name implies it, I'm not looking to cut corners with my car in the future. I chose the name long ago because I'm a DIYer and like to do my own custom tweaks. Which usually is much cheaper than paying someone.

Also, as of now I just want the car running so I can assess things further and have some proof of life.

Thanks!

 

Simple thing to do is to attach a fuel pressure gauge to the end of the fuel with the DME relay removed and jumper the relay terminal slots in the fuse box to activate the pump. The fuel pump should activate and the pressure gauge should read 34-37PSI. Just make sure you have a battery with a decent charge and is at least at 12V. This is how the fuel pump and fuel pressure regulator are tested at the dealer.

If the fuel pump checks out then re-insert the DME relay and turn the ignition to the on position without cranking the engine. You should see the fuel pressure again in the mid 30's, if so your DME relay is also good.

 

Sounds like a plan. We had stuck a battery in it and tried to start it with a couple gals of fresh gas, but it just spun and spun. Listened to try and hear the pump kick on, but nothing there either. We did get it to crank the first time we gave it a little taste of starting fluid, so I'm pretty convinced its a fuel issue. We just didn't have many tools or parts on hand to work with at the time. And next time I check it out I was hoping to get it running the same day.

 

I would also check the speed reference sensors towards the read of the engine. if these sensors are bad or gapped improperly they will cause a similar situation you are experiencing.trying jiggling the sensors and see if there are any changes and try jumping the dme relay(search for it on here).good luck

 

I don't have my WSM to quote from... the fuel pump will not activate unless ~ 300 RPM is sensed by the DME. Unless you jump the DME relay, the motor must be cranked to run the fuel pump.

Clark's Garage, Troubleshooting Fuel Supply Problems

 

The hose from the tank to the pump could be the problem. When I got my car the fuel line in that section was collapsed. Pull the fuel pump cover and check.

 

I always recommend installing a FP gauge to help with diagnosing issues.

It may be a few things but I have found that very often the injectors seize up, or the pump freezes.

Do the 3 wire jumper and check fuel pressure. That will narrow it down quite a bit.

 

Just trailered the car in question home! I'll report back tomorrow after I get some wrench time with it.

Thanks!

 

Quick and cheap test - take the cap off the front of the fuel rail, find a way to catch the fuel (the right size hose will fit over the threads) and crank the car - you should get a significant amount of fuel. This will also help flush the lines.

Problems with cars that have been sitting for a while are typically electrical issues.

 

I lucked out guys. I drained all the old fuel out, cleaned the strainer and changed the fuel pump. After I added some fresh fuel, it cranked right over!

Next ill be changing the line that comes off of the fuel filter because I spotted a small leak. Ordered a fuel filter as well. Looks like I'm on my way!