86 Carrera Problems

Paul Shepherd · 08-09-2009, 05:50 PM

Hello everyone im new to the forum and have a problem with my carerra.
Sorry if the explanation is a bit long winded but wanted to explain events accurately.
My wife took the car out yesterday and after about 10 miles the engine died and she likened it to running out of gas. After a short wait the engine started and she carried on to her destination.
The car then sat about 3 hours and then I arrived to drive it home but it would not start, would turn over fine but no hint of it firing so a truck was called to deliver it home.
Once the car was unloaded in the garage i tried it again and it would just fire for a second and then die.....it did this twice then nothing.
Got up this morning and it fired up straight away and again about 5 times so i left it idling for about 10 minutes before switching off, waited another 10 minutes and tried again........nothing again.
Just wondering if anyone has had a similar problem or any ideas of the cause.
I thought of the dme relay but not sure if they fail intermittently or not.
any help will be greatly appreciated
Also would like to know what parts are different from a US spec car to mine which is european spec in case i have to order parts
thanks Paul

bondavi · 08-09-2009, 06:56 PM

Might be cold solder joints in your DME, or an intermittent fuel pump/coil issue. I feel your pain, am going thru something similar.

Oregon Cab · 08-09-2009, 09:32 PM

Just did this last week. Search my posts on DME Relays. Towed twice. It was a finally a fuel pump despite the shop wasting 2 days on DME diagnostics and 2 relays. They finally hit it with a mallet during cranking and it started. They said Carreras are always Relays not pumps.

Same issues. No fuel, intermittant works, then doesn't, dies after a while or not. Starts later. Relay is $46 and FP is $265. I got the pump and now all is perfect. The shop ate 2 days diagnostics.

Paul Shepherd · 08-09-2009, 11:14 PM

thanks guys for the replys.
Oregon have just come in from solving the problem to see your post.
Did the same thing, tried jumping the pump and nothing so removed the tray and lightly tapped the pump and away it went so problem solved.
Looking at the pump it appears to be unservicable so a new pump is probely the go....is that correct?

tomphot · 08-10-2009, 04:19 AM

I went through the same thing - finally diagnosed as a flywheel sensor issue.
You have 2 of them - speed and reference senors that sit on top of each other. Changed them both out and I no longer have any problems.
Do a search for these sensors and you'll see others who had the same issue - also look on how to order the same parts as non-P-car to save big bucks.;

tnchris · 08-10-2009, 08:10 AM

I wouldn't necessarily rule out the DME relay yet. I had a similar problem last winter, driving for about 20 minutes and the car died on the freeway. After sitting for about 10 minutes, it cranked back up and made it to work before dying again. I got a new DME relay and haven't had another problem for months.

Oregon Cab · 08-10-2009, 08:15 AM

Paul, replace the pump and relay... unless you want to have them both fail again on you someday.

Love beating parts with a hammer. How old school is that!

86 911 Targa · 08-10-2009, 08:48 AM

Paul,

Do yourself a big favor.

Replace the relay.

Or carry a spare.

Cheap insurance.

Good luck,

Gerry

AVIMAX · 08-10-2009, 08:50 AM

Paul,

I'd replace the DME relay or at least keep a spare just in case. I had the exact same problem with my 1986. Died, then after a few minutes stared up again and drove for a while. Then it died again and would only start and die, not run. Eventually it wouldn't even catch, just turn over. After I put in the new relay, no problems. Out of curiosity, I took the old relay apart and found that one of the solder joints had cracked causing it to fail. So in answer to your question, yes the relay can be a little intermittent before it completely dies, probably as the solder joint is failing, slightly cracked solder, then completely cracked solder.

Ryan

kidrock · 08-10-2009, 10:45 AM

swap out the DME relay first. If the problem isn't solved by this, I believe it will be your fuel pump. Before replacing the pump, spray some carb cleaner or quick-start fluid into your vacuum. If the car starts then dies, you've found your problem. If not, you will need to diagnose your electrical/electronic systems.

Paul Shepherd · 08-11-2009, 09:41 PM

definetley fuel pump have ordered a new one plus a DME relay for the glove box
thanks guys

tnchris · 08-12-2009, 07:17 AM

A new relay, even in the glove box, is always good insurance for these cars.

kidrock · 08-12-2009, 07:33 AM

Sounds great, Paul...glad you were able to locate the problem.

When installing that new pump, be careful while tightening the hose connection onto the check valve on the pump. Mine broke off fairly easily last time.

86 911 Targa · 08-12-2009, 07:40 AM

Paul,

Our experience with DME relays is that they fail on an intermittent basis.
Most likely from contact corrosion, as they do run toasty warm.

Glad we could be of help.

Gerry

dshepp806 · dshepp806's Garage

Yeap,..best to change them out on a "preventative" basis (that's what I do,..every year: fresh copper contacts:::::::the rule my 2 cents). Now I just couldn't stand my DME or fuel pump to be starved for current from corroded contacts!!!!!!!!!!!!!! I keep my voltage drops to a minimum.....!!!!!!!!!!!

Best,

Doyle

widgeon13 · 09-04-2009, 11:38 AM

Quote:

Originally Posted by kidrock

swap out the DME relay first. If the problem isn't solved by this, I believe it will be your fuel pump. Before replacing the pump, spray some carb cleaner or quick-start fluid into your vacuum. If the car starts then dies, you've found your problem. If not, you will need to diagnose your electrical/electronic systems.

Ok, I'm having a no start problem on my 3.2 Carrera. Was running fine and now just cranks but will not fire. I replaced the DME (w/ a new one) but still the same, cranks but no start. When I turn the key to ignition, I don't even get any noise of the fuel pump running. Have checked all the fuses and checked the fuel pump fuse specifically, every thing looks fine, no mouse chewed wires, no fuel leaks or gas odor.

In the quote above it mentions starting fluid sprayed into the vacuum, just exactly where do you do this in the engine compartment, anyone have a picture to show where to inject the spray?

colinsco · 09-04-2009, 01:25 PM

I just ordered a fuel pump to address the same symptoms. New DME relay did not resolve but removing front skid plate and gently tapping the fuel pump with a rubber hammer has got me going again twice. You can validate that the pump is at issue if you short across the top of fuse number 6 to the bottom of fuse number 5 (count from the firewall). If the relay is at fault that should cause the pump to whir by bypassing the relay. Good luck.

widgeon13 · 09-04-2009, 01:54 PM

Does it bypass the fuel pump relay (red) or the DME relay? I switched out the red relay for a black one and turned the key and also got nothing, suppose that doesn't tell me anything if the second (new) DME relay is (or could be) bad as well.

Thanks very much for the timely reply. At this stage I need all the help I can get.

colinsco · 09-04-2009, 02:24 PM

My '88 does not have the separate "red" relay and I would be surprised if yours does but I'm not the expert (I don't know if it will help but my fuse block has 21 fuses and 6 red relays) . I confirmed that the DME relay on my unit functions as the fuel pump relay in one of my searches on these forums, probably for ("fuel Pump" AND Carrera). You may want to include the year and add in searches related to DME. If I find the posts that helped me I'll forward to you.

widgeon13 · 09-04-2009, 02:42 PM

When I look at the schematic it doesn't show a fuel pump relay so must be the DME that performs that function in 84 Carrera