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Alright gents, I've been through just about every thread on every forum I can think of that contains the words injectors, ecu, ex. I need someone to crayon and construction paper this for me because I'm about ready to start throwing parts at it.
Baack story - Buddy's truck ran and drove fine, let it sit for 5 months while he was away on business and it didnt start when he got back. Charged up the battery and changed the fuel filter ran fine for a little while. Died on his way home one day and it wouldnt start up again. He called me.
I'm not terribly familiar with 22re's other than the fact that they're great engines with way too much wiring plastered all over them, so I did some basic checks before I went to some research.
It has good spark, runs when starter fluid is introduced to the throttle body, good fuses, relays check out, no fuel pump noise when cranking. Jump the fp/b+ ports in diagnostic hub doesnt kick the pump on when the key is turned on, however the pump does kick one when I apply 12v directly from the battery supplying fuel to the rail. At this point it will crank and run for split second before dying.
Moving forward, I realize theres no CEL when the key is turned on. Should be there for a few seconds and then go away but it's not. I then turned my attention to the ecu.
It's getting power, and the resistance from the grounds on each of the connectors is about 1 ohm. I tried manually turning on the check engine light fromm the ECU with the "W" port (purple wire) and it came on.
I'm lost, and my head hurts from so much automotive electricity. Who feels like providing me with some direction so this thing can be on the road where it belongs? It's too pretty to be sitiing in my garage not running.
Correct
b+ from the diagnostic port to ground 0.171 volts
I thought so too, for that reason every ground in the engine bay had 80 grit taken to it.
i havent found any wires chewed but but since it was stored outside and i did notice a good bit of moisture behind the left and right kick panels no blown fuses or anything though
Both have good continuity
Primary fuses are good, the AMs I'll check after work tomorrow
I also went through and tested everything based on the FSM earlier today
I'll put up my readings tomorrow to see what you think
Most are within spec, some are kind of wierd
The B+ pin gets it's power DIRECTLY from the EFI Relay. The EFI Relay gets power through (duh!) the EFI fuse, and is closed by IG2 (part of the ignition switch) THROUGH the IGN fuse. The ECU has nothing to do with it, so stop blaming the ECU!
The EFI relay does need a ground to the coil (pin 2), but randomly fixing grounds, if that happened to fix anything, would just be an accident. (There are several grounds on this vehicle.)
Feel free to re-check those fuses, but try listening for the EFI relay to close with key-on (it's under the hood on mine, and I think all 2nd gens have it there). If you can hear it, that doesn't prove it's ELECTRICALLY okay, so pull it out and test it with your multimeter. If the relay is good, it's just plain-ole trace-the-voltage back to the battery, forward to B+.
I believe the EFI relay is in the fuse panel in the driver's kick panel for 1988 trucks. PO had replaced my relay with a jumper wire and the wire crumbled and truck would not start. I bought a gently used EFI relay and replaced it.
Edit: And your friend is very lucky to have a friend like you.
No worries wyoming, I appreciate it.
I was messing around with a noid light and decided to check to see if i was getting a pulse from the injectors while cranking.
Sure enough I'm not.
Scope, the EFI relay checks out per the fsm, something around 75 ohms. As far as continuity between them is concerned, could you lay out the crayons and construction paper for, you know (cough).. some one in the future that might not be very good at vehicle electronics and needs it broken down a bit more haha
For troubleshooting this I want to know where you would start, where you'd put the positive and negative leads, all that good stuff.
Well it's an exciting night. I feel stupid but, that's how we learn.
So I blanked out everything I had already diagnosed and went back to the basics.
CO Thank you for leaning me to check the continuity in the line between the diag port and the pump
It got me to a point where i really understood how to multimeter works, rather than just positive/negative 12v
Scope I have to thank you for laying out the EFI curcuit for me. It got me to where the issue was in sequence.
So I started with the key on, checking the voltage to B+ in the diag port. Wasn't getting 12v there so I moved onto the Engine fuse and the EFI fuse.
Both had 12 volts, so then I decided to test the EFI Relay. Pulled it out, tried to test for continuity on the coil.. nothing..
Tried the other two, nothing. The brain bulb happened here, at which point I said to myself "test the voltage and jump it to see if this was the issue"
Sure enough I jumped the two connections closest to the firewall, check engine light came on with the key on
Jumped the test connector for the fuel pump and it came on, started and ran beautifully.
It stumbles a little bit at idle but atleast it runs now.
Again thank you guys for all your help. It means alot and I know he'll be happy that his truck is up and running again.
Awe you found the problem before I had a chance to post (and see the thread) lol. Was going to say before you attack ECU or even grounds, get your B+ fixed, that goes to the ECU as well, as well as a BATT wire (power all the time). ECU has like 4 grounds for different things lol.
Good luck finding the bad spot in the wiring, I don't have a wire diagram for that gen of truck to reference, but I do have next up gen 1990.
.... Pulled it out, tried to test for continuity on the coil.. nothing..
Tried the other two, nothing. ...
Isn't using a multimeter just the cat's meow? No more of this throwing parts at a problem you just can't see (because you didn't know how to look.)
Now that you are nearly a multimeter guru, let me suggest some terminology. A multimeter never reads "nothing." It can read 12volts or 2.4amps or zero ohms or infinite ohms (often shown as 0L, also used for "overload" on voltage scales). Each of these means something. So when you tested for continuity, I'll bet you found infinite ohms (an "open"), but if you called it "nothing" that could be "no" ohms (a "short").
Definitely scope. I do this stuff because I enjoy it and its a useful skill to learn. I just got a bit too analytical without more solidified variables.
I just hope this helps someone out in the future.
I'm probably going to end up buying this truck from him in the future so, there's going to be more fun stuff on the way for this one.
Good catch on the coil mention, it didn't stick out to me, probably because "nothing" meant nothing to me lol. I don't have the coil ohm specs on hand or I'd post them. Generally one coil is around 0.4-1ohms and the second is a little more (don't remember off hand).
It does seem to have two separate problems (fuel pump running), and something ignition/wiring related at idle/staying running on it's own.
When I referred to "coil" is was referring to the coil in the EFI relay. There is no spec for that http://web.archive.org/web/201209051...95efimainr.pdf . It wouldn't help much, anyway, because ordinary sub-$400 meters don't have a lot of accuracy below 1 ohm (lead resistance, etc.). And a relay coil would either fail open (broken wire), or possible fail to a short which would blow a fuse. So all you care about is "some low resistance" vs. infinite.
So I drove the truck to work today to test her out and she runs pretty well. Comfortable ride, smooth shifting. It ticks a bit more than I'd like but I'll probably pull the valve cover off and check some clearances and check on the timing chain guides. After that, crankcase treatment, fuel treatment, and double checking moving connections underneath and she'll be good to go.
04-03-2017, 07:50 PM
