Hi All,

Sorry if this gets a bit long-winded, just trying to describe my issue thoroughly. If you can make it to the end, PLEASE give me feedback

Stats:
89 TPI engine & harness / 5.7L / Serpentine belt / No 9th injector / TH400
Engine and harness were pulled from the same donor vehicle
Engine has been sitting for +1.5 years (MMO'd cylinders before initial crank)

Here is a quick rundown of where im at with the swap:

Engine/trans/t-case all mounted. Starter wired thru the factory toyota harness. External fuel pump, controlled by the chevy ECM. Using all relays etc. from the donor vehicle. Recently discovered a blue wire coming from pin B-6 (IIRC) on the ECM plug which lead me to believe the vehicle was equipped with VATS. Purchased a programmed adapter from tpiparts.net to disable/simulate the 30hz square wave signal (the most nerdy thing i have ever said i think...) required by the ECM to allow the injectors to pulse.

Here is the problem:

Engine will crank and has spark, but will not fire. Since I have air and spark, i must believe I am not getting fuel. With the key in the "on" position, the fp relay energizes and i can hear fuel moving thru the fuel rail, and back into the tank. I have tried the screwdriver method to listen for injector pulse while cranking, and can not hear any clicking. Have also used a digital multimeter across one of the fuel injector clips, and can only see about .5 volts at any single injector clip while cranking. Fairly certain the injectors are not pulsing.

My troubleshooting:

Started with the VATS-removed PROM from tpiparts.net. Next, checked all the grounds listed as necessary (IIRC d-1, d-3, d-6, d-10, MAF ground, ESC ground, and ALDL Terminal A) in the swap guide (sorry, cant remember the name ATM, it came with the eng/harness/trans) that I am using. I do not have the ALDL connector, so I cant test that ground. I am assuming that the ALDL was grounded somewhere between its connector and the under-dash connector (white plastic, pinned A-K IIRC). All of the grounds tested ok, with minimal resistance. Finally, I looked to the reverse/neutral safety switch signal wire going in to the ECM and, if I understand correctly, that wire needs to be grounded for the ECM to allow the engine to run, so, I grounded it :P

My questions:

What am I forgetting?
Shouldnt I be able to see +12v at any injector clip momentarily during cranking? (Wondering if the multimeter cant react fast enough? Need to use a noid light?)
Can anybody tell me specifically which grounds (on the pinout) the ECM uses to ground the circuit for the injectors?
Am I correct in assuming that I can simply ground the Reverse/Neutral Safety switch signal wire to the ECM to pass that logic check?
Do all the common grounds (eg: any time any single ground is ganged together with other grounds like D-10 is ganged to the fan relay grounds) need to be grounded even though i test the terminal as grounded?
Any relevant thoughts/comments/suggestions?

Appreciate any help I can get, thanks!

 

well you are light years ahead of me on the wiring aspect ,but all your theories sound pretty good to me.

you said it has spark right? Is it a good strong spark and not just sparking randomly.

as for the voltmeter catching that signal in time at the injectors. i highly doubt it would.

you can rent noid lights from autozone thats probably where i would start next.

i would triple check that your are getting adequate spark personally.

i would be more inclined to thinking the ignition control module in the distributor may be bad or the pickup coil in the distributor.

just my thoughts off the top of my head though.

g/l with it and keep us updated with what you find out.

btw autozone can also test your ignition control module in store for free too (i work there lol).

as long as you go in at a not to busy time we can test a lot of stuff for you

 

Keep in mind that the injectors ground through the ECM,The ECM grounds to the back of the heads. The injector driver switches ground not 12v, that being said you should have 12v on the injectors with the key in the run position.

 

Flaming Ford - It seems to be getting healthy spark, and its not sparking at random. I pulled 2 of the plugs, cranked it and watched them fire in order as i would expect.

Battman -

To clarify, when you say "ground through the ECM", does that mean physically through the metal shell of the ECM, or through one of the several "system ground" wires in the connector pinout? If its grounded thru the ECM case itself, i would think it would be grounded to the chassis via the 4 mounting bolts. How is it originally grounded to the back of the heads?

Thanks!

 

Its grounded through the grounds in the ECM pinout, and those connect to the back of the heads on the engine. do you have 12v on the injectors? have you sprayed some starting fluid in the TB and see if it hits?

 

Have you got the OE fuel pump oil pressure switch installed?
ECM needs to see voltage from pump being run by OP switch as well as the signal from dist before it will fire the injectors ( assuming VATS is deleted).
While engine is cranking only the OP switch is operating the pump ( after engine reaaches 4 psi ); not the relay .
Possibly hot wire the pump to run full time ( at the relay so ECM sees pump voltage ) and see if injectors will pulse?

See start up sequence
http://www.corvettebuyers.com/c4vettes/l98.htm

Typical wiring



TPI fault finding

http://www.chevythunder.com/Flow%20c...0Chart%20Pages

GoodTPI swap info
http://www.chevythunder.com/chevythu...troduction.htm

 

From the 165 pinouts looks like D15 and D16 are the injector inputs to ECM
http://www.chevythunder.com/fuel%20i...0ECM%20PINOUTS

As far as I am aware that only affects cranking through the starter enable relay which you are not using.

 

"Its grounded through the grounds in the ECM pinout, and those connect to the back of the heads on the engine. do you have 12v on the injectors? have you sprayed some starting fluid in the TB and see if it hits? "

Battman - I have all of the grounds from the ECM thoroughly grounded to the firewall, rather than the back of the engine. The engine is grounded to the chassis and body via a 4 ga ground strap. Yes, I can measure +12v at the injector clips when the key is in the "run" position. Isnt apparent to me that the extra resistance of not having them grounded directly to the engine would cause the injectors not to fire. I have not tried the starting fluid technique yet... Opinions?

"Have you got the OE fuel pump oil pressure switch installed"

Vetteoz - Yes, I have the oil pressure switch installed, and a fresh oil change before attempting any cranking. Are these switches prone to failure? It has been sitting for quite awhile, but I cant imagine any reason for it to have ZERO oil pressure during cranking.

"Possibly hot wire the pump to run full time ( at the relay so ECM sees pump voltage ) and see if injectors will pulse?"

I tried this, only not thru the relay, just a direct line from the pump to the battery... I will have to try this.

Where did the graphic come from? Its not the typical alldata printouts I have been working with. A vette book or something? Ive been a regular reader of chevythunder.com for awhile now. Great resource!

Is there any way to check for the distributor reference signal? I have the 4-wire connector hooked up to the back of the dist. cap, just assuming that its good...

 

That is the 3 wire combined switch / OP gauge sender unit that came on a '89?



I that case jumper the 2 heavy wires ( red and org ) at the switch; the pump should run full time

From '85 Corvette FSM , typical of 85 - 90 setup
Gotta go out ; will lookup dist signal procedure when I get back

 

PM me your email address ; have something you might be interested in

 

I'll throw in my two cents. The reason for grounding everything to the block/cylinder heads has more to do with noise /ground loops/offset for the sensors and timing, should not effect the injectors firing.
A digital multimeter is too slow to "see" the signal accurately, but if you put a digital multimeter set on the lowest ac voltage range, accross the injector (with the injector still hooked up electrically) you should see a difference in the reading when the engine is turning over. On some meters you may get more response on the dc voltage setting. It won't read 12 volts but if the reading changes from around zero volts to 0.5 or 1 volt while the engine is turning over you know some kind of signal is there, unfortunately you can not be absolutely sure it is enough of a signal to fire the injector. You wrote you have 0.5 volts when cranking so something is happening.
You have determined +12 is on one side of the injector. I assume this is true for all the injectors. Of course these wires (one for each bank) must be "hot" in run and start switch positions. The other pin (light blue wire for odd cylinders, light green for the even cylinders) connects directly to the ecm. (At least on my 85, 89 colour might be different).These wires connect to the ecm on 4 pins in total, two for each bank. Internally the ecm connects these pins to ground to fire the injector.On my car the ecm uses the connector pins, not the case for grounding. Make sure all the pins coming out of the ecm that should be connected to ground are. When I converted my car over to megasquirt I had problems because I did not have power from the ignition switch connected correctly. Make sure the wires that are supposed to be hot in start and run are hot in start and run.
The easiest way to make sure wires like the distributor reference signal are connected correctly is to remove the connector from the ecm ( I would disconnect the battery before doing this). Run a jumper wire from the approprate pin on the connector (ecm end of cable) to ground. (take a wire and strip both ends, one can be attached to the car frame, the other end is jambed into the connector) Measure the resistance at the correct terminal at the other end (in this case the distributor end) to ground with the multimeter. It should be near zero ohms. Remove the jumper from the connector (ecm end) and measure again. It should now be a very high reading. You have just proved the wire goes to the right spot and the wire is not damaged or shorted. Always remove the connector from the ecm and disconnect the battery before doing this as you could damage something.
If you have turned the engine over lots and the plugs are not wet yet then you know it is not getting fuel.
Are your supply and return lines hooked up right to your fuel pressure regulator,not reversed, and the regulator is ok? After the fuel pump has been on the fuel rails should be pressurized with gas and stay pressurized for a while even if the key is off. If you push in the bicycle valve on the rail gas should shoot out (put a rag underneath to catch the gas, have a fire extinguisher handy, etc.), or use a pressure gauge if you have one.
Using starting fluid is a great labor saver since if you can't get it to fire with fluid, it will never start without it. Just don't use too much.

 

I think your grounds are fine, Next I would ohm out each of the injectors. if its the factory injectors 1989 is the worst year for injector shorts, They should read arountd 11 - 15 ohms, any thing lower than that and it will overload the injector driver and not fire the injectors correctly. also how long did the engine set before the swap took place? possibly the injectors could be gummed up? I would spray some starting in it ans see if it fires up

 

The second year I had my tpi it barely started, ran like a piece of crap. I think the problem was the last couple tanks of gas I put in before winter were 10% ethanol and it killed 3 or 4 of the injectors. They would ohm ok in the car. When I took them out and hooked an air line to them and put 12 volts on them, some did not flow any air. I tried filling them with carb cleaner, letting them soak for a day and trying again, no joy. I even tried an ultrasonic cleaner. I made sure my new injectors were ethanol compatible.
If you take your injectors out and test them, don't make a spark because if they open the residual gas inside them sprays all over or you could borrow an injector and plug it in to one of your injector plugs and put an air line on it, then you could tell if the injector is being fired.

 

"That is the 3 wire combined switch / OP gauge sender unit that came on a '89?"

- vettoz: In the picture you posted, the switch looks similar to what I have, but in my application it is lower on the block on the the driver side, just above the oil filter. Also, does not have the brass fitting coming off the block, just the sensor. IIRC there are 3 wires going to the switch, one of which is tan/white which i have spliced into, going to the fuel pump. (I am trying to pull this all from memory as I dont live where my truck lives I only get to work on the beast on Monday and Tuesday if im lucky)

"Make sure all the pins coming out of the ecm that should be connected to ground are."

- redcorvette: Ive double and triple-checked these grounds (IIRC d-1, d-3, d-6, d-10). I will double check the ignition switch wiring on Monday. Your suggestion does make me wonder if i am getting the amperage I need out of the ignition switch, the Toyota wires coming off the switch are ~14-16ga, wonder if i need to beef them up... As far as checking the harness for faults etc. I traced every wire from the ECM connector to its respective plug on the harness (and labeled each wire) before installing the harness in to the engine bay.

"Are your supply and return lines hooked up right to your fuel pressure regulator,not reversed, and the regulator is ok?"

-redcorvette: Yes, i believe the supply and return lines are hooked up correctly. The 3/8" line on the fuel rail is hooked up to the fuel pump via a metal line, with about 1' of high pressure rubber fuel hose, and section of metal line I bent to fit along the valve covers going to the back of the block. Have not seen any fuel leaks at any of the connections. Fuel is returned to the tank via the 5/8" fitting on the fuel rail along parallel plumbing for the feed line. Also, I can hear fuel spilling back in to the fuel tank when the pump runs for ~2 seconds when the key is turned to the "run" position. Have not yet tested the regulator operation.

Will the injectors fire at all if there is insufficient fuel pressure in the fuel rail?

"I think your grounds are fine, Next I would ohm out each of the injectors."

- battman:

IIRC the resistance ALLDATA quoted was higher than that, maybe 15-18 ohms, but yes I have tested them, and they all read nominal based on the numbers I was working from. I have had the engine since October 2008, and my buddy probably had it for ~6 months before that. It was going to go in his buggy, but he needed the moolah. (800 bux for the engine, harness, ecu, TH400 trans, NP241D T-case, and the AA adaptor for the trans/tcase... SCREAMIN deal... although the t-case was in exchange for labor... ) Intend to use some injector cleaner if i can ever get it to fire...

Put a fresh 5 gallons of gas in the tank when I re-mounted it up in the bed, so i dont think its fouled/has water in it.

First thing I will be trying when I get over to the truck on Monday will be starter fluid in the intake manifold...

Appreciate all the suggestions/feedback etc. Will update as I continue troubleshooting...

 

Not that I believe it affects your stating problem but in the stock setup as shown in the diagram I posted above;
Orange is 12V feed direct from battery via fusible link
Red is feed to fuel pump ( and on it's way the reference signal to ECM showing pump has power ).Joins the orange from FP relay and passes through the pump fuse
Tan is the oil pressure gauge wire to ground through the variable resistance of the sender unit

 

Damn dude, you are up early/late!

So one of the wires going to the switch should be a constant +12? Didnt expect that, was expecting that switch was a thermocouple.

Side note - im hoping to hook the oil pressure display in my factory toyota dash to the oil pressure sender/switch. Is it a voltage coming out of the chevy oil pressure switch? Does anybody know the range? 0v - Xv?

 

As with the majority of gauges the wire from the gauge is to ground through the variable resistance of the sender unit
Typical setup



Have you hooked the red and orange up to anything? Polarity doesn't matter ; is only a switch
As noted above if the ECM does not see pump voltage when cranking
( which can only come from the OP switch; relay is off line during crank ) it will not pulse the injectors
That is why I suggested jumpering the relay because that would simulate the same effect

 

Um, ok, not to be a pain here... but....

The oil pressure switch is backup power for the fuel pump. If you look at the diagram, the pump can receive power (and thus, the ecm a signal as well) incase the relay fails. The ecm will prime the system for two seconds when you initially turn the key to on, and then, will again engage the relay when it sees a reference signal from the ignition module. Doesn't matter if you are cranking or not, or, what the oil pressure happens to be. If the ecm sees the engine is turning, it energizes the relay.

I don't think that is the problem though, you need to get the noid light, and see if your injectors are pulsing. The ecm uses the same reference signal from the ignition module to decide if it should bother pulsing or not. A digital VOM will not react fast enough to show if this is happening. A noid light is the best way to see, you could also try using a test light with one end on a +12v source, and the probe on the ground wire for the injector..... might work.

 

i'm with ploegi, don't over complicate this to badly. First rent a set of test lights..... its free in the long run. See if you are getting injector pulses, probably not..... from there follow the schematics from the injectors back and keep back probing to see where you are losing your signal... (my guess is still probably at the distributor, modules and pickup coils do some crazy ****).

 

Update:

So, i finally got over here and have been troubleshooting for the last 5 hours or so. Here is what I have come up with...

The engine will catch/hit/cough when using starting fluid in the intake manifold. Woo hoo! Signs of life! *Smokes 2 cigarettes and chugs a beer*

Hooked up a noid light and while cranking, it goes on and off. I was suprised however that it isnt an on/off like a light switch, rather a slow on, slow off. The light seems to get dimmer the longer I crank, but it has a pretty definine on/off cycle... (Have the battery on a trickle charger now, starter was sounding a little anemic)

Tested all 8 injectors for resistance, here is the breakdown (ohms):

1 - 16.2
3 - 16.1
5 - 16.2
7 - 16.0

2 - 16.0
4 - 16.2
6 - 16.2
8 - 16.3

I would think these values were a little on the high side, but with all of them in such a close range, I am assuming they are "passing". (2c anybody?)

Next went on to test the fuel pressure. After key on, 2 seconds of FP on, the pressure jumped right up to 44psi and held there pretty well. Took about 7 minutes for it to drop to 40psi. Maybe a small leak somewhere, but I wouldnt think it would keep the engine from firing.

Along the way somewhere I listened for injector pulse using the screwdriver method, and I can not hear any definite "clicking".

Double checked all the grounds, and re-sanded the mating surfaces down to bare metal just to make sure.

Am currently following the troubleshooting steps listed at chevythunder.com, but not having any luck yet.

So, it still wont start... Seems to me that the injectors arent firing. Any thoughts?? Gonna grab some chow and get back to it.

 

know why? the engine is embarassed to be seen in a toyota! lol :P if you have no injector pulse, i would replace the magnetic pickup in the dizzy, this tells the ECM that the engine in cranking and to fire the injectors, it's a crankshaft positioning sensor of sorts, tey rust up and spot working, i just replaced my entire dizzy cuz of it

 

Would this be the rusty pickup chevy8588 posted about? How much rust is too much? :P

 

The "slow on, slow off" thing concerns me. It really shouldn't do that. It should be just like someone flipping a switch, as that is exactly what the computer is doing. This could be due to a poor ground, but, I think you covered that..... Now, why it does that.... I haven't a clue. Almost like there is a capacitor in the circuit somewhere?

Quick edit here: Replacing the pickup coil, and module, are fairly trivial tasks, and would probably be well worth the effort. Gotta pull the distributor to do it though.

 

yah they are more like a camshaft sensor actually, but i think you are quite aware of this (just trying to sound more spot on).

9 times out of 10 when you see a noid light pulse eratically like that its the ignition control module. the other .9 it's the pickup coil. the other .1 i would expect ecm/ground/wiring.

just my opinion.....

although i am like ploegi the slow off and on is odd and i can say i've never honestly saw that before truth be told lol.....

Now test out your dizzy already i have a good one at my parents house. it came out my my perfectly fine running camaro..... if you want i'll ship it to you for the charge of shipping (can't beat it for the price). You will need your old cap and rotor though as i yanked mine off.

let me know an address if you want to take me up on it and i can send you my paypal for shipping$ if you want......

g/l man should be a fun toy soon as you have this worked out.

 

Since i figured out how to send pics from my phone to my email, thought id throw up a couple more...

"Replacing the pickup coil, and module"

@Ploegi: I will have to test them later tonight/tomorrow... Will keep it on the short list

"test out your dizzy already , i'll ship it to you for the charge of shipping (can't beat it for the price). "

@flaming-ford: Thanks very much! Very generous of you. I will try to get it tested tomorrow, and ill PM you my email address if I need the part. Am trying to find a method for testing the ignition control module ATM. Im not at home and dont have accesst to my ALLDATA info :P

 

You can yank the module, and take it to most any parts store (advance, or whatever you have in your area) and have it tested.

It has been my experience though, that a fair number of the testers really aren't that accurate....

 

once again ploegi is spot on.......

i work at a parts store currently and i would say our accuracy is about 80%........ either way the main thing is this if they test it bad they will return it for you even if its not bad normally...... (hence there fault not yours).

btw when you do go and test it test it about 5 or 6 times, thats what i normally do at our store. it should be hot enough that you cant touch it by the time your done testing it (hence the big heat sink on the back of the modules).

 

Pulled the ignition control module on tuesday and had it tested. It passed 10 times out of 10 tests... When I yanked it, i noticed that it was only held down to the distributor with one VERY rusty 3.5mm bolt. The other bolt that should be there was missing... After spending about an hour trying to find matching hardware to replace the 2 bolts with, and had to quit for the day. Turns out its not easy hardware to find... Started at ACE, then a automotive/machine shop, finally a place called Fasteners Inc. No joy. Will have to drive half an hour out to AAA Metric on monday to get the bolts.

Where im going with this is, apparently the ignition control module grounds thru the metal base of the distributor, and looking at the bottom of my module, there is evidence of arcing, and with only one bolt holding it down, i wouldnt be suprised if it was getting a crappy ground, which *hopefully* will be the reason the ECM isnt getting a good distributor reference signal.

Also picked up a new distributor pick up coil, as suggested by chevy8588, although the coil on there now passes a resistance test with 830 ohms...

 

Got it running about a month ago! Woot! Turned out to be a simple stupid solution... When figuring out the plug wires, set the engine to TDC and looked at the rotor position on the distributor. It was right in between two of the pickups. Initially chose the point that would be next in the rotation as the #1 cylinder... yeah, you know what they say about assumptions... So anyway, swapped the plug wires around so that #1 was in the right place, and it fired up. I havent been able to get it to idle yet, but if i bump the throttle when it wants to die, it keeps running. Maybe a bad IAC? Any thoughts are welcomed...

I do have a quick question about water lines. Im digging thru my box of parts, and i found a small U-shaped hose, and im wondering if it is supposed to go from below the throttle butterfly, down in to the lower plenum. Can anyone confirm this for me? Its the only place i can envision this piece of hose running... See attached picture.

Thanks!

And if anyone wants to throw in their 2c about the no-idle issue, it would be much appreciated.

 

Lose it
In the stock setup hot water is flowed through the IAC housing to prevent the throttle blades from icing up.
Most bypass it and run heater hose direct from intake to heater

 

Hey, sorry to bring back an old thread and all, but i need some more wisdom.

So... I got the truck moving, drove it around the neighborhood a bit for about a month when it suddenly quit. The engine stopped running, and would not restart. It will crank all day long, but wont run. I was fortunate enough to be at the top of a hill near home, and coasted it back to the garage.

Some time later, I started troubleshooting and found that the battery was completely drained. Guessed that i had a hot wire running to ground that was draining the battery. Started by checking both toyota and chevy harnesses (im running a combo of both to keep all of the factory body wiring intact) positive leads at the battery with the multimeter for resistance to ground. Found a potential problem and fixed it.

After some more diagnosis, it has no spark. I hooked up the SES light and jumpered the appropriate wires to pull error codes. The SES light flashes a code 12 over and over again, and nothing else. My documentation says code 12 means "ok" and also (?wtf) that there is no distributor reference signal to the ECM. So, I figured that the pickup coil in the dizzy gave up the ghost, so i replaced it and still no spark.

The only other thing that changed close to the failure was wiring the alternator. I found something (cant remember where) that said that the third wire to the alternator goes to a switched +12v source when the key is in the run position. (The other 2 go directly to the battery and starter)

Questions for the forum:

What can i do to test the ignition coil and ESC? (The autozone by home can test my ICM when they find the stupid adapter that they lost...)
Is there any way to test the ECM without having a donor firebird/camaro/vette to hook it up to?
My other problem is that it only ran sweet at one throttle position, otherwise it didnt want to accelerate well. Havent yet "tuned" the TPS...


Any relevant replies would be awesome, thanks.

 

Bueller? Bueller?
Ploegi? Vettoz? Redcorvette?

Anybody throw in their 2c?

 

Alt requires resistance in the form of a light bulb or resistor on that wire to excite the alt. If not there then alt will not make power



As a note.
When a thread gets this old, it is sometimes easier to start a new one to get more attention as a lot of guys don't go back on old posts
Just a brief outline of what you have done ( TPI in Toyota ) or a link to this page to refresh guys memories
then your current problem