byrdman454

Can someone give me some hints? My buddy has a '84 Euro that won't start. He has checked the fuel and there is fuel up to the rails, so the relay and pump are working. There is also fire at the spark plugs. It does not appear that the injectors are firing. What could be the problem?

Rez

Turn the key from off to on, but don't crank, does the fuel pump buzz? (i.e., working). The 80-84 (hopefully Euro) have the cold start injector, or 9th injector. Something may be wrong with it. I'd check the fuses to the injectors, may be an easy fix.

https://www.928gt.com/default1.htm click the fuse/relay link.

heinrich

are you sure all wires are firing? does it try to start? check the little belt between the distributors. If ignition is truly good, check the second stages up front near hood latch, and troubleshoot normally for LH issues.

jyoon

if you can smell some gas and you have spark, check the tempII sensor. my car would not start when that was disconnected. is should ohm out at 3+- at room temp.

John Speake

Has your firend checked fuel pressure at the rail ? What has been done to the car since it last ran ?

Rez - the Euro is an LH engine, no cold start valve/9th injector.

byrdman454

Heinrich--The belt that drives the distributor is intact. It does not hit any cylinders, it just cranks and cranks.

jyoon--I will check the Temp II sensor, but shouldn't it at least try to start if this was out?

John--He has not checked the pressure at the rail, only to be sure fuel was getting to that point.

He did remove the airbox and poured fuel down the throat and it did run. It definitely seems like a fuel delivery problem. What about the computer, if it went south would it not fire the injectors?

What should we check next?

Thanks

k1woods

Also, check the grounds - especially the one's on the right camshaft housing. As suggested, follow the LH testing procedures.

heinrich

I think it is obviously an LH signal thing. There are some great procedures posted for that

John Speake

LEt us know what has been done to the car (if anything ) since the car last ran properly. This may help to narrow down the possibilities.

A proper fuel pressure check is needed. Failing that, with a suitable comtainer you could check that fuel is being returned to the top of the fuel tank when the engine is cranked. This means that tghere is sufficent pressure for fuel to be pasing through the pressure regulators.

Pull an injector connector, and on the socket check with with a voltmrter from each pin to chassis. One side will have +12v all the time the ignition is on. The other side should show +12v when the ignition is on but engine not cranking. With the engine cranking you should see the volts on that side go down by about 0.1v. This is because the pulses are fast compared to the crank speed of the motor. It's a crude check but at least it will confirm that the output stage of the LH is OK.

Rich9928p

Defective relays and fuses are often the problem of no start conditions. First remove and inspect the fuel pump fuse.

One simple test for no start is to remove the following relays
- spark (EZF or EZK)
- LH
- Fuel Pump

Use a jumper wire and bridge relay socket pins 30 and 87 of all the relay sockets (do not drive the car with sockets jumped).

a. the fuel pump should run at all times when the jumper is in place (if there are any fuel leaks, immediatly remove the jumper!!)
b. for early EURO LH systems, the fuel pump relay also powers the fuel injectors, there should be 12V (nominal battery voltage) at the fuel injectors. Other 928s have injectors powered by different circuits)
c. the LH and EZK modules are powered

Crank the engine. If it starts, you have a bad relay. A relay jumper will need to be pulled to stop the engine once running.

To find which relay is bad, remove the jumpers one by one, replace the relay and attempt to start the engine. If it doesn't start, you found the bad relay.

Warning, label relays and have a position chart. If a relays are put in the wrong socket, the engine may never start.

If it doesn't start, you need to look elsewhere.

The early 1984 - 1986 LHs do not have the 1987 and newer "hybrid circuit" problem, so defective LHs fall into the "normal electronic module death" pattern.

byrdman454

Heinrich, where are these procedures? I did a quick search on Rennlist, but really did not come up with anything. Is there an outside source for these LH troubleshooting procedures?

Thanks

Rich9928p

I have a lot of tips on my website www.electronikrepair.com - look to the diagnostics page. Even if the specifics may be for S4 and newer 928s, the theory is the same for the previous generation 25 pin EZF and LH controllers.

Specific info for your '84 Euro: EZF relay VIII, LH-Jetronic relay XVI, and Fuel pump relay XVII.

These module connectors pin-out descriptions will come in handy.

FlyingDog

Was the Timing belt removed? If so, the oil pump may have turned and the distributers could be out of allignment.

Search for a thread about Tony's injector troubles after swapping injectors for his supercharged shark. It is full of specs and procedures for checking every possibility with the injectors.

byrdman454

I am back trying to work on this no start Euro. Here is the entire story.

The last owner had a good shop do a bunch of stuff in July '04. They replaced the fule pump, timing belt, ing. rotors, distriib. belt, all 8 injectors and seals, all belts, spart plugs, fule filter sock, diustr. caps and installed a used ignition control unit from 928 INTL part number U92861812400.

Then in September the car was towed in with a no start condition. The shop replaced the engine control module with a used one from 928 INTL part number U92861812300. They also replaced 3 relays. The car was running again and the owner traded it for a Mercedes.

The car was running fine and now it has died again. I have jumped the relays like Rich suggested. The fuel pump runs, there is spark at the plugs, but the plugs are completely dry. We cannot hear the injectors clicking. The dealership told me that if you pour gasoline down the intake that the car will run. What can I check next?

I am a little new to these older cars since I have an S4. There is a strange box located at the fuse panel. The label says "FAC-3 Fuel Control Module for Porsche 928" The box has an address from California on it. Is this part of the Euro to US conversion or is this supposed to be there? Does anyone have any info on this?

There is a green wire hooked up coming from the ignition control unit harness. Is this the crappy gas connector? Should this be disconnected? What other power robbing things should I look for when they imported it to the US?

Thanks
Mike Byrd

FlyingDog

The green wire is probably the low octane retard wire. The FAC-3 box doesn't sound right. It is probably some sort of federalization part.

This thread has a ton of info on diagnosing injector problems. A lot (but not all) should apply to an LH Euro.
https://rennlist.com/forums/928-forum/180091-87s4-no-start.html