newkie

So ...

I decided to buy all three wire harness that Lindsey racing offers. Very easy to install and stylish. And to get rid of the useless connectors everywhere and get the new version which actually is easy to loosen.

Anyway. After installing everything right (and I've looked through it again), I get no spark. To make a long story short.

Twelve volts on both wires of the coil, no power to injectors. coil seems to be firing pulses even if they are weak (i get no spark though, tested with an ignition lamp and the thing reacts. But it does not blink. It just kind of dims upp and down real fast.

The injectors have no current. DME relay is tested by all the rules and it works great. No fuses are blown. I can bypass the DME relay and get power to the injectors. But then I get no trigger signal (tachometer does not jump).

My conclusion tells me that the coils in the DME relay receives no power and therefore do not provide power to the injectors. But how do you solve that problem?

any other thought? Feel free to speculate!

The car is a Porsche 944 turbo -1989

Happy Midsummer to all of you!

newkie

Ok.

Lets start with something easier. How does power get to the injectors? You get a "trigger" voltage from the dme computor to the DME relay that activates a small coil in the DME relay, right?

I seem to have no power over the Actuating circuits on the DME relay. What could cause this? Alarm-system? Immobilizer?

Comon guys im really stuck here!

Zeff

does everything in the dash move when you key on? does the tach bump but no firing?

newkie

Yes tach bounche and everything. The car seems normal. Just no power to the injectors and using a lightbulb to test the ignition only gave me faint diming.. no flicker.

CyCloNe!

would a DME relay contribute?

newkie

I dont think it would. The DME works perfectly fine, tested with a 12v source. The mechanical parts work fine, so does the elctrical (circuits gets completed)..

My next move will be removal of the after market alarmsystem.

Zeff

The tach bump but no start makes me think the DME ecu. My ecu had some bad solder joints.

What exactly did that aftermarket alarm do? Was it wired to shut down ignition?

newkie

I tried a known working DME comp. No difference. The allarm has 3 circuits. Starter, ignition/injectors and one more..

I read here on the list that some members experienced that the OEM alarm broke. This resulted in the immobilizer deactivated for the starter but not for ignition/injectors. This could only happen to cars newer than 88 and mine is an 89..

Could the alarm really cause this?

doabarrelroll

Maybe try bypassing the factory alarm system to rule that out? There is a write-up on clarks-garage.com

User 52121

Ok this might be a long shot, but if it's the same issue....

So a friend of mine (xupkid2 here on RL) has an '89 Turbo Cup replica. He ran into a no-start issue over Labor Day weekend up at Road America... which turned out to be the factory alarm. If he jumpered the DME relay, the car started and ran fine. But would refuse to start if he put the DME relay back in. After several DME relays, and an investigation by one of the technicians from Chris Schuh - they determined it was the alarm. Apparently the factory alarm does it's disabling thing via the DME relay... but jumpering it bypasses that.

Try jumpering the DME relay and see if the car starts.

Jim

newkie

I will try a bypass of the original alarm.

Jupering the DME relay gives me power to the injectors. How ever, if i bypass the dme relay. I get no tach bounce. Strange huh?

hot-J

Is your airbag harness connected to the airbag computer?
Main ground on bellhousing clean and secure?
Speed/reference sensors connected backwards? Try switching them.

84GTi

ever find out what it was?