dragonrob

I changed the relay and now have 12 Volt's on w23 I have found that I have 2 bad relays. Thanks again so much for your help!

dragonrob

I have worked on it today but can't get spark. It has power to the computers but I don't know why it won't fire I don't have any negative voltage on pin 18 so I am stuck at this point.

Ducman82

so you had spark but no injectors, and now you have injectors but no spark?

docmirror

Yeah - um, huh? Now no spark?

Pin 18 of what?

dragonrob

I have power 12v to the fuel injectors but I tested the plug wires for spark and it isn't firing. I figured out the pin 18 on LH it is going negative voltage.

docmirror

Pin 18 of the LH is the injector firing pulse and it fires negative when turning on the injectors. So - it's supposed to be at 12V along with the other terminals from the IMS to tie point 1 and 4 of the print. The injectors stay both pins at 12V until they are told to fire by pin 18 of the LH going negative. If you have a solid negative signal on that pin, the system isn't reaching ready state, which is why you have no spark.

You will need to find out why you have no spark first. The injectors will never, ever deliver fuel to the engine until there is ignition to burn the fuel. A good place to start is the CPS, which is called the 'speed sender' on the print. Also as noted before, the coding plug must be inserted with the proper pins for the 89 harness. At this point, not sure how to set the coding plug.

dragonrob

There is 12v only on one pin of the injector plug also the Ims relay is lighting green LED .I will check speed sensor.also yesterday I changed the sensor on the back of engine that gets pulse from the flywheel.

RFJ

I am sorry but i do not understand this??? wiring and all is free for the taking and??

dragonrob

Rfj ? This is about putting 89 engine in 86car.

dragonrob

Today I have POS 12 v at pin 18 and injector plug has 12 v on both sides.

dragonrob

Today I have put the 86 computers and harness back in and have spark and it is firing .I put the old 30 PSI reg in but I don't think this will work so I will change back to the 55psi and see what it does. If it works I will get the porken chips and go with that setup.

ramcram

Now I think you are on the right track.
What injectors are fitted?
The 86 5.0 litre motor had larger capacity injectors than the S4. If you are using stock 86 computers, they will me matched to the high out put injectors and 30psi regulator.
If you up the rail pressure to 55psi, this will match the S4 injectors but who knows what result you will get from the wrong computer.

dragonrob

I am using the 55psi fuel pressure and 19lb injectors it is wanting to start but acts like timing is off.with the 30 PSI reg I don't get any fuel pressure.

ramcram

IIRC the 19lbs injectors are the S4 ones and use the 55psi regulator, so aren't a match for the 86 controllers. I don't know how that combo will result.
when one of my 86 ROW cars tried to start but sounded like timing wrong it was the 2 fat green wire at the controllers, that come from the ignition triggers were crossed over.

docmirror

Double check spark on ALL plug wires. I want to know for certain that you are getting spark at both dist, and all plug wires. you can just use one spark plug and move it from ign wire to next ign wire.

Verifying that you now have spark to all plug wires, put them back in the holes while manually tracing back the wiring to the numbering embossed on the ledge of the two dist caps. You need to look close to see them. Insure that the plug wires are in the correct holes for the firing order on both sides. It's easy to get wrong.

Now, remove your fuel pump relay and do not jumper the fuel pump. You will need an assistant for the next test.

Using two cans of cheap carb cleaner(do NOT use brake cleaner, or starting fluid); While the assistant cranks the engine, spray carb cleaner into the MAF but try to not hit the fine hot wires in the middle. This should provide plenty of fuel to check that all cylinders are firing. You will need to feather the throttle cable manually in a spirited attempt to compensate for the amount of carb cleaner entering the engine, and try to maintain a somewhat stoichiometric ratio(Yeah - I know....). Run the car for a few seconds and it should be obvious that all cylinders are firing or not on carb cleaner.

If all cylinders fire on carb cleaner, shut off the engine, put the fuel pump relay back in the board socket, install the bone stock FPRs, and the bone stock 19Lb injectors, and go buy/borrow a 'noid light'. It will be about $6-7 and you don't need the 8 pc kit. With a fully charged battery, insert the noid light into each injector connection sequentially and crank the engine each time. Note the intensity of the noid light as you go. Injector harnesses are notorious for faults.

Report findings.