Hello HT. I recently bought a 1991 integra. The story behind the car is that thie gentleman who had posession of the car bought it about a year ago. He was told that it was an obd1 swap in the car it has a b18a1 in the car he drove the car until this past fathers day weekend when the car bogged down and came to a stop. From that point it would no longer fire up. He took it to a shop and their diagnosis was a bad ecu. fast forward a couple months to when i go see the car....... I was aware of what the diagnosis was so i brought along another ecu in hopes to fire the car up and drive away unfortunately it was not the case. I first discovered that the car has a push button start which means the key does not have to be turned to the start position to start you just turn the key to the on position hit the button and it "should" start unless i am misinformed ?. The car surrently has an obd0 to obd1 jumper at the ecu attached to an obd1 pr4 ecu. The engine bay plugs and distributor plugs are in obd0 form. Im not sure if the distributor was changed. The injectors are obd0 as well with the factory resistor box still in place. I checked the main relay and it indeed was bad so i then replaced with a new one. The fuel pump now primes and fuel gets to the rail with great pressure behind it but will not start. I tested the spark and it was good as well. I then put a squirt of starting fluid in the throttle body and the car fired up. At this point i figured something is wrong with the injectors so i tested the harness for power with the key in the on position. The left side pin which on all clips the color is red was getting 12 volts so i guess its safe to assume the resistor box is good? i then checked the right side pin of the clip which are various colors 1 was brown the next was red the next was lt blue and one was yellow from those i didnt get anything. The thermostat housing is securely fastened and fuses seemed to be good as well. My question is does the distributor or any piece in the distributor control the ground pulse to the injectors? and what else should i check?

 

Also when i crank the car the MIL is off like its supposed to then comes on while cranking and when i stop cranking the MIL goes away i have tried to pull code but none seem to be there ?. I have searched and searched that is how i was able to get to the point i am right now. I almost feel like i am out of options on what to do. Any help is appreciated

 

you shouldnt see 12v on the separate colored injector pin. that is the ground side and is closed by a driver in the ecm.
heeres what id do; remove one of the 194 bulbs from your corner marker. peel back the tangs. disconnect an injector. insert the tangs into the injector connector. crank the engine and watch for the bulb to flash. if it flashes, injectors are pulsing. if not, i would check your powers and grounds at the ecm connectors. should be 2 powers; one keyed, one constant. and probably about 3 grounds. youll need to find a pinout for the connectors to test. the pinout is key. if all powers and grounds are functional, test for injector pulse at the ecm connector. if no pulse, check crank signal. if you have crank signal, problem is ecm related. maybe a problem with conv. harness

 

awesome thanks for the input. I am going to try all of this. Can you tell me how to test for crank signal please? is it in the distributor where i test? and i test for resistance correct?

 

Make sure IGP1 and IGP2 have power at the ECU/ECM.

If you have power at the injectors, it indicates the fuel injector relay in the PGM-FI Main Relay is working, however it does not necessarily mean you are getting power to IGP1 and 2, [supplied by the fuel injector relay], on the stock harness it will be the only two (2) yellow/black leads at the ECU/ECM, plug(s), make sure there is power on both at the ECU/ECM side of jumper harness.

I assume the ECU/ECM you tried was a known working one. 94

 

not resistance, no. voltage. and i would test at the ecm. no need to jump around to different connectors. its all right there.
you can use a voltmeter or test light to check for signal. crank signal on these is an mp generator, i believe, so just 2 wires. back probe the ecm connector. set the voltmeter to read volts. unfortunately, i dont have adiagram though. so youll need to get that part figured. although, if you have spark, you should have crank signal anyways. sorry my bad. you can skip that part then

 

ok well before i got this message i did what the haynes suggested which was test resistance at the distributor plug and it checked out according to the book. Like you said if im getting spark then the crank signal would be out of the question? The ecu was "said" to be good. It was not taken from a working vehicle. I am hoping to have one from a working vehicle for testing tomorrow. On another note the main relay im not sure if i get 3 clicks. I get the 1st when you turn on the key and lights come on and fuel primes, then i get the 2nd after MIL goes out but im not sure about the 3rd. Now the car has a push button start 1 wire ran straight brom battery to 1 side of the switch and from the other side of switch to starter sol. so i dont physically turn the key to start i just turn to the position just before crank. I put it back to stock meaning using the key but when i turned to crank nothing happens meaning the starter doesnt engage? possible ignition switch? and could that affect this 3rd click? i just bought the car last weekend in this condition and trying to work out the kinks. I appreciate all of your help guys. I have seen numerous other posts on here while searching and seems like you guys really know your stuff so thanks for any and all input.

 

Igp1 and igp2 both have power. Funny thing is when I test ground at the ECM pin #2 it goes away when I turn key on and main relay clicks? And when I say ground goes away I mean there is no continuity between that wire and chassis ground when it goes through the relay.

 

I jumped the grounds at ecu and the mil stayed solid and the relay never clicked?

 

The first and second clicks of the PGM-FI Main Relay are very close together, the first click is the injector relay turning on, [power at the injectors and at IPG1&2 indicate injector relay is working] the second click is the fuel pump relay turning on, [fuel pump priming indicates the fuel pump relay is working] the third click is the fuel pump turning off after priming.

What color is the wire on the pin #2 ground your testing, [original harness not the jumper]? 94

 

The color is black with silver marks. I got the car to turn over by connecting a new ground from core support to valve cover and stud it only lasted 2 seconds. I then attached new grounds through a piece of home electric wire to chassis engine and vc but couldn't get anything? I am super stumped but feel good just knowing there is some hope.

 

have you tried checking for pulse at the injectors with a 194 bulb?

 

the injectors did not pulse the bulb on/off.

 

i also plugged in an obd0 ecu to the factory car harness and the mil stays on and doesnt go off. Also the blinking LLED inside the ecu does not blink a t all. Is this normal?

 

did you check for pulse with the obd0 ecm installed?
the led will blink if a code is stored. it is not normal for the mil to remain lit

 

i did not check that since the mil stays on and relay doesnt open or close

 

you need that ecm pinout to check your powers and grounds

 

The 91 ECU/ECM harness/plug(s) have 3 chassis grounds for the ECU/ECM one is brown/black and the other two are blacks, [may have "silver marks"] all three of them must have full continuity to chassis ground at all times.

"I got the car to turn over by connecting a new ground from core support to valve cover and stud it only lasted 2 seconds"

I assume when you say "turn over", you mean fire/start/run and not just crank, [starter working].

If so, it sounds like you may have a grounding problem, I would check/redo the main grounds, batt. post and cable clamp, batt. to chassis ground and chassis to engine ground.

The VC ground is not a main ground it is a "unifying ground", because of the HG the head is somewhat isolated from the block so Honda uses the VC ground to insure the head, [that has the sparkplugs grounded to it] has a good chassis ground.

You did say you have good spark, but redoing and insuring the VC ground is good is a must to insure that spark is strong.

DO NOT just eyeball the ground connection, disconnect them, clean both contact surfaces, [eg; batt. neg.(-) post and inside of cable clamp] and reconnect making sure connections are tight.

Grounding may not be your problem, but it is worth eliminating as a possible problem and definatly can't hurt to do on a car that is 21 years old.

If you have not already, do the same with the thermostat ground(s), [remove/clean/reconnect]. 94

 

Ok I wil remove and clean for sure. Can you elaborate on why the ground to ecu goes away after main relay is turned on? I know 1 of them does but the other is supposed to be ground all the time?

 

i even tried to jump the ground to them via the black/brown wire and nothing changed?

 

A ground, [input] for the ECU/ECM should never "go away" they are constant, if you lose continuity to chassis ground for any reason then the ground connection, [to chassis] is no good. 94

 

Ok well guys thank you so much for all of your help and input. The problem was something I checked twice before. The ecu fuse was blown 10a under hood. I checked with my electrical meter and gave me 12 on both sides when I checked previously however I never pulled the fuse and visibly looked at it to be sure. Ok I wil remove and clean for sure. Can you elaborate on why the ground to ecu goes away after main relay is turned on? I know 1 of them does but the other is supposed to be ground all the time? Thanks everyone once again.

 

iPhone copied and pasted stuff that it shouldn't in post above. Problem was ecu fuse. Disregard the rest.