I have just completed an JDM Turbo II swap into a 90 NA.

I have no injector pulse on the front primary injector when using the USDM ecu(370). When I swtiched over to a JDM ecu(374), there was no pulse to the secondary.

This engine has the vacuum removed for the emissions and the EGR removed. If that changes anything.

PLEASE HELP! This car has been here for too long and needs to get out of here.


Thanks.

 

Sounds like you have two bad ECU's if both refuse to run a pair of injectors.

Have you checked continuity on the Jspec's harness(if you're using that one)?

 

Your going to have to do better with describing the problem.

Are you saying that with the 374 the car starts and runs but the secondarys don't open when you reach 3500rpm and are under load? That's when the secondarys come on, so that's why I ask. You just complained about the 374 because the secondarys did not work. You didn't say the primarys didn't work....so I assume they do.

 

Sorry, I meant the rear Primary works on the 374 ecu. I had rear and secondary mixed up. They both run, but they both sound like they are running on one rotor.

Compression test was done on a Mazda C/R tester and were both good. The 374 is a KNOWN good ecu. There was continuity to both injectors.

 

If you pull the plug off the ECU, you have batt voltage at each primary socket on the plug? Key to ON? I think you said that though.

Blank look here. Got me. ECU works on another car from what you said. So it can't be a dead driver in the ECU.

Maybe put a meter on the plug socket, key to ON and shake/wiggle the harness b/t the ECU and the injector while someone looks at the meter to see if the 12v reading opens while you wiggle the harness.

Maybe take another look at the EMISSIONS harness that goes to the injectors from the ECU, and make sure the plugs on that harness are coupled together really good (inside the passengers compartment).

Hard problem there.

 

Does the emissions equipment have any effect on this?

I really need this car out of here.

 

No. Emissions has NOTHING to do with the pulses to the fuel injectors. Nadda. If you ask me, it has to be an intermittent in the harness b/t the ECU and the injectors that are not working.

I mean, the injectors have 12vdc constant on them all the time the key is to ON. The ECU gets its *timing * signal to put a ground on them from the cas.

The 12v to the injectors comes from a plug on the Emissions harness. That harness runs from the ECU ....around into the engine bay and across the front of the engine to the injectors. One plug on this harness is located inside the passengers side compartment. It does not connect directly to the ECU, it connects up above and to the right of the ECU. Waaay up there. Maybe a bad connection there?

WHAT IT REALLY COULD BE, SINCE YOU DID A SWAP OF ENGINES............There is what is commonly called a GROUND RING TERMINAL on top of the rear rotor housing. That is the ground for the ECU which in turn means FOR THE INJECTORS also. It is held on with a bolt. It cannot be seen without removing the intake
manifold. Do you remember something like this????? It has either two or three BLACK wires on a ring terminal.

I am NOT talking abou that simple *** ground stap that runs from the wiper area to the bell housing (close to being a nothing).

 

Here's what the ring terminal ON TOP OF THE REAR ROTOR HOUSING looks like:

 

the ground is good but still one pulsing injector

 

I don't mean to hijack the thread but how do you check if the injectors are pulseing? Just a regular test light? (I'm having a similar problem thats why I'm asking)

 

Yup, that terminal has been grounded.

Also, I've tried both Ecus on another vehicle and they both worked fine. So the ecu's are good.

I've also jumped the wiring so that the one injector that's getting signal is running both injectors. It runs pretty smooth now. But that does not fix the problem.

Wierd I tell ya. WIERD

 

i know this is an old thread but i'm having the exact same problem with the rear rotor not getting fuel (primary injector) if i bridge the negitive pulse from the front injector to the rear injector it starts. also to note the fuel pump doesn't come on unless i jump it at the check connector.----ok to refresh the story this is a 88non turbo N/A chassis and im putting in a jspec 89 t11motor using the N/A non turbo harness using all turbo sensors and jspec ecu. i know the turbo will cut fuel to the rear rotor under too high boost but i dont know if it cuts the primary or secondary injectors i am also aware of the pins to the ecu to disconnect 3d,2k,2r
any thoughts would help thanks

 

ok it starts on the n/a spec ecu and runs ok (wont idle--bigger injectors probally) so the ecu is bad i guess.it looks great inside nothing burnt should i waste my time finding a jspec ecu or is a n/a just as good if not where to get it repaired when nothings burnt. also what ecu should i be looking for for a n/a turbo
ps: my years are wrong its a 89gtu-s car and a 90 jspec t11 engine
also fue pump wont kick when cranking but works when running(removed jumper while running)