Originally Posted by Srwilliams (Post 7431222)

Bazaar:

You know I never checked the DME relay because since the car was running great before I powder coated I assume that the DME relay was good. But I am a little confused. I thought the relay next to the DME (brain) was the fuel relay and if it was no good your fuel pump would not have power to work. Since my fuel pump is powered and spraying its butt off I assumed that the relay was good. Could that DME relay prevent the spark that I am missing. Here, I am trying to educate myself

Originally Posted by bazar01 (Post 7431240)

There are 2 sets of contacts inside the DME relay. One set for the fuel pump which evidently works. The second set of contact supplies the injectors and DME computer (ECM) which also works because the injectors are getting power. So the problem is not the DME relay. You can try to change it just to try. It does not hurt to have a spare anyway.

You can do one more check to see if the DME computer (ECM) is getting power at terminals 18 and 35. If it is getting power, then ECM is suspect.

Originally Posted by Srwilliams (Post 7431015)

Doyle:

You read correct. the pulse is going to the coil, but there is no output of the pulse from there. There are two wires to the coil. When the car is off they both read negative and when the car is on they both read positive (or vice versa). Doesn't the fact that these wires are reading positive and alternatively negative mean that they are good. What do you mean by a possible bad coil wire---could you direct me?

Originally Posted by Srwilliams (Post 7430823)

1. First, pulled the injector plug as y'all instructed and put a voltage meter on the right prong. Surprisingly, I was getting 12 volts on all of the injectors with car turned on.

2. Went to left prong of each injector and was getting ground signal on each injector with car off. Did you pull out the ECM connector when you did this?

3. As yall instructed I then moved to test all of my ground points. Found the one behind the fuel filter on the drivers side wall of engine and it was properly grounded, as well as the ground strap on the front of the intake manifold (hope that is what it is called---But trust me I found that strap that you guys posted for me). One poster said on his 87 he had a ground point at the negative side of the battery (8 inches long). On my 87 Carerra, 3.2, I could not find that front ground wire.) Me and a friend mechanic looked all over by the battery---could'nt find.

3. Here is where the problems kick in. Although I was getting 12 volts to the injector, they still were not pulsing. I got noid lights as you guys instructed and I and the mechanic put them on the injectors---no pulsing.

4. Went to check for spark. No spark or fire at the distributor.

5. Checked coil. With engine off, got negative on both wires and postiive on both wires when the engine is on (this may be reversed but you get the idea. Power was going to the coil, as well as ground. But coil was not sending pulse to the distributor to cause arc, fire, or spark (one of them is correct). Everything completely dead at distributor. We pulled a spark plug and put it in the ignition wire that goes either from the coil to the distributor or to the coil and nothing (mechanic did this test so I am ignorant here)

5. Sully sent me a diagram of the readout of the DME. I went to the interior of the car and checked the output of the DME (brain) to the coil (Pins 1&19). The brain was sending out a pulse to the coil as the diagram said it should. HOWEVER, the pulse that is sent by the brain is not being read by the coil and then sent to the distributor (hence no spark). What type of meter did you use to check the pulse at pin 1 and ground pin 19? Did you actually see a high and low voltage signal?

Originally Posted by Srwilliams (Post 7431993)

Bazaar:

In answering two your two specific questions.

1. No i did not disconnect the ECM (brain on the inside of the car) from the ECM harness when i checked the ground on each left injector prong.

2. When I checked pins 1 & 19 I used a voltage meter. the mechanic who was reading the meter said it was pulsing. I did not see it, and I really do not know if he knew how to actually read the meter. I simply went off of his word.

Could you share with me your suspicions that prompted your questions because i am truly stumped

Originally Posted by bazar01 (Post 7432102)

1. The reason I asked if the ECM was still connected was because with the ohmmeter probe on the ground pin of the injector plug and the other ohmmeter probe to the nearest ground point in the intake manifold, that just indicated that the injector plug has a connection to the ECM ground circuit. A better way is to test continuity directly from a disconnected injector plug to a disconnected ECM plug so you can tell if there is a disconnect someplace in the firewall connector.
2. It is really hard to see the pulsing on a digital meter display. A scope meter will be best. With your test, you really cannot say the ECM is providing the ground pulse to the ignition coil.
The ignition coil pulse signal is a series of fast 12V and 0V switching signal. 12V saturates the ignition coil primary coil and zero volt causes a collapse in EMF on the primary coil to induce the high voltage spark on the secondary high voltage coil. The high voltage gives the spark plug the high voltage arcing.

Are you going to send out your ECM for testng? You can just wait until you get the ECM back to confirm your ECM is good, then troubleshoot further.

Originally Posted by Srwilliams (Post 7432142)

Bazaar:

I am going to send out the Brain now. I will get it back and then troubleshoot from there. Thanks so much for you and everyone else's patience and guidance.

Originally Posted by E Sully (Post 7432614)

Just to give a little information on the coil, the black wire is a 12V source when the key is in the run or start position to the coil +15 terminal. The green wire goes from the coil '-' connection back to the DME, which makes the connection to one of the brown ground wires connected to the intake runner to trigger the spark. There is no signal on the green wire, just a series of intermittant ground connections to trigger the spark. It works like a set of electronic points opening and closing the ground connection.
http://forums.pelicanparts.com/uploa...1368128469.jpg

Originally Posted by dshepp806 (Post 7433067)

Spoke with a VERY knowing Porsche guy today and he was quite concerned (with all of the disconnects) that the sensor connections didn't get swapped on the reconnect, as this would give you the indications you are experiencing. Hopefully, you've already put that suggestion to bed.

Best!

Doyle