No-Start Condition - Suspected Injector Pulse Issue

[GOLIGHTLY]

All,

I think this my first time contributing to the Mitsubishi forums so thank you for having me.

Running into a pretty specific problem with a 1996 Montero SR 3.5L, with a good fuel pump (tested). I have spark and (sure SOUNDS like, when using starting fluid) compression . When I set the key to the 'ON' position, I get no fuel pump prime, but it runs as it should upon cranking. I have appropriate voltage at the one injector I can access without removing the intake manifold (would love to avoid doing so, as I just completed a timing belt/water pump/cam and crank sensor job) and injector actuates upon being grounded.

I believe I have an injector pulse issue but am having a hard time tracking that down, so my questions are as follows;

1- Is there anything glaring that I'm missing here, off the top of anyones head?

2- Are there any better recommended wiring diagrams than the factory service manual?

Thank you for yalls time in advance.

 

[Salonika]

So what is the problem? Do you have a no start condition? What about ignition system?

Give us more detail about your problem.

 

[CharlieNorth]

Are you absolutely sure you have all five timing marks on the pulleys where the belong and both sensor property installed and connected. Since you have a 96 you can pull data on this.

 

[GOLIGHTLY]

So what is the problem? Do you have a no start condition? What about ignition system?

Give us more detail about your problem.

Yes sir, probably should have mentioned somewhere other than the title. No start condition.

Are you absolutely sure you have all five timing marks on the pulleys where the belong and both sensor property installed and connected. Since you have a 96 you can pull data on this.

Timing is aligned correctly and both cam and crank sensors are brand new, installed per FSM and returning signal when cam/crank fins pass through the sensor.

Curious if there are any common issues at the transistor or at the ECM regarding grounds/power outputs?

Thank you guys for the replies.

 

[CharlieNorth]

Factory sensors or generic market?

 

[MummifiedCircuitry]

You're 100% sure you're getting fuel to the rail? You've checked the diagnostic test plug for the pump on the firewall and pulled the fuel line to visually see fuel?

 

[Salonika]

Give more detail on the starting fluid thing you mentioned…….describe what you are doing and what happens.

 

[GOLIGHTLY]

You're 100% sure you're getting fuel to the rail? You've checked the diagnostic test plug for the pump on the firewall and pulled the fuel line to visually see fuel?

Actually, would you expand on the "diagnostic test plug"? My vehicle simply has a pressure line and a return line going into the firewall, with no visible location for a fuel pressure tester (none visible on vehicle, and none that I could find in FSM schematics). If I'm missing the boat on that, that would be a huge help. To clarify, when I say I'm getting fuel, I mean that I have a confirmed good pump, and my pressure line at the firewall is definitely under pressure (cracked the connection coming from the firewall ever so slightly and had fuel eagerly weeping from the connection after about 3/4 turn). Though to repeat, I don't have a prime at KOEO, only running pump at crank. If it were a fuel pump relay issue, I wouldn't have pump at crank though, correct?

Give more detail on the starting fluid thing you mentioned…….describe what you are doing and what happens.

I tested spark at the coil and at the passenger side bank cables, both good. All plugs confirmed good. Thus, I used a very small amount of starting fluid directly through the throttle intake, as a tertiary test of spark (I know, starting fluid can be a red herring for spark, thus did that last). Engine made a clear attempt to fire, used a little more to confirm and listen for compression. All that to say, starting fluid was just used as a third confirmation of spark.

 

[GOLIGHTLY]

Apologies for the long-winded responses, just trying to give as much detail as possible. Have found multiple threads on this around the web, and nobody provided much info/follow-up as to solution, so kind of just providing all this in hopes of keeping symptom-troubleshooting-solution in one place for future folks.

Thanks for yalls time so far.

 

[CharlieNorth]

Actually, would you expand on the "diagnostic test plug"?

I tested spark at the coil and at the passenger side bank cables, both good.

Diagnostic plug is where you plug a scanner into.

You state "at the coil" there are 3 of them.

The fuel lines do not go "into the firewall"
There is a single wire connector on the firewall that you can apply 12V to and run the pump.

 

[GOLIGHTLY]

Diagnostic plug is where you plug a scanner into.

You state "at the coil" there are 3 of them.

The fuel lines do not go "into the firewall"
There is a single wire connector on the firewall that you can apply 12V to and run the pump.

Ah, meaning OBD. My scanner is in another vehicle so will plan to bring that this evening.

Yes sir, "at the coil", meaning I tested the coils (all three of them). Thus to clarify, also tested all 3 cables and all 6 plugs.

I'm referring to the fuel line connectors labelled "17" in the FSM. They recede down along the firewall. Do you have any intel on where to find that "single wire connector"? I assume it's one of the connections on the wiring harness?

 

[MummifiedCircuitry]

It's usually taped up on the firewall, passenger side engine bay, near where ABS would be. I'll try to go take a picture in a 97 SR in a bit.

 

[MummifiedCircuitry]

The black/white wire. You take that cap off and theres just a single terminal in there. You can run a meter on it to to get prime/run voltage and if I remember correctly I've applied 12v to it to run the pump directly for testing

 

[Salonika]

Also just a food for thought reminder, an incorrect mixture can also sound / seem like nothing is happening……other than eventually smelling gas in your exhaust. I’m thinking something like a fuel pressure regulator being shot….fuel might be going in but no boom. Plus your injector pulse issue, if true, would likely not prevent the engine from running at all, but it might make it run rough or not keep running, but I don’t think a problem with one single injector would cause a flat out no start condition.

 

[GOLIGHTLY]

View attachment 703548

The black/white wire. You take that cap off and theres just a single terminal in there. You can run a meter on it to to get prime/run voltage and if I remember correctly I've applied 12v to it to run the pump directly for testing

Oh gosh, my ignorance is in full force right now... I assumed that those were connectors for scrapped emissions equipment lol. Now that I'm educated, I'll test that first thing tomorrow. Thank you for taking the time to get me a photo (side note - I like that placement for what I presume to a dual battery setup... is that a drop-in kit of some kind or a "home brew"?)

Also just a food for thought reminder, an incorrect mixture can also sound / seem like nothing is happening……other than eventually smelling gas in your exhaust. I’m thinking something like a fuel pressure regulator being shot….fuel might be going in but no boom. Plus your injector pulse issue, if true, would likely not prevent the engine from running at all, but it might make it run rough or not keep running, but I don’t think a problem with one single injector would cause a flat out no start condition.

You may have just keyed me in the right direction on something I assumed was a related/associated ECM issue. I don't get a fuel level indicator signal on the dash either, and I may be mistaken, but looking at electrical diagrams a busted sender may contribute to effectively all of the above symptoms. A spectacular miss on my part. Thank you for pointing in that direction, and I'll document back here once I have a look into that in the morning before work.