Calling 3FE Fuel Injection Experts - Bad Signal Generator in the Distributor?

[TBauer]

OK - I have traced my FI problem to a bad signal generator in my distributor - I think.

According to my manual, "if the ECU does not recieve ignition reference pulses from the electronic ignition system, the fuel pump will be shut off after 2-3 seconds.

I am going to put the fuel gauge on tonight and check the time the fuel pump cycles, but that is essentially what my engine will do - shut off after 2-3 seconds if it decides to kick.

I posted a thread last week - "Fuel Injection System Issue - Won't Start" - there is a description of my issues, sorry, it's a long thread.

Anyway - I have fuel pressure (46psi), ignition, air. Am getting a 51 code on my ECU, which corresponds to either no throttle position signal, gear selector, or air conditioning signal to the ECU. I checked the TPS (ohmed it out according to manual) and only one of the measurements was off...could be bad, so I'm trying to find a tps locally that I could just plug in to see if it starts, but I'm thinkin it's something else.

Any experience with troubleshooting this 3FE would be appreciated.

Cheers

 

[lowtideride]

are you getting a check engine light at start up?

 

[Moby]

I don't have the manual in front of me but I seem to remember that there is a signal from the MAF as well (like air has to be entering the engine or the pump shuts down). I could be total off base but I seem to remember something like that.

You've jumped the terminals and checked the troubleshooting codes?

 

[FJ40Jim]

OK - I have traced my FI problem to a bad signal generator in my distributor - I think.

According to my manual, "if the ECU does not recieve ignition reference pulses from the electronic ignition system, the fuel pump will be shut off after 2-3 seconds.

I am going to put the fuel gauge on tonight and check the time the fuel pump cycles, but that is essentially what my engine will do - shut off after 2-3 seconds if it decides to kick.

I posted a thread last week - "Fuel Injection System Issue - Won't Start" - there is a description of my issues, sorry, it's a long thread.

Anyway - I have fuel pressure (46psi), ignition, air. Am getting a 51 code on my ECU, which corresponds to either no throttle position signal, gear selector, or air conditioning signal to the ECU. I checked the TPS (ohmed it out according to manual) and only one of the measurements was off...could be bad, so I'm trying to find a tps locally that I could just plug in to see if it starts, but I'm thinkin it's something else.

I see no logic in the above conclusion.
If the engine fires, then it is getting crank reference signal.
And there is a 51 code that has nothing to do w/ CKP signal.

To eliminate CKP as a suspect, test it per the manual.

Then repair the TPS circuit and clear the code.

Just my .02

 

[billmc]

I checked the TPS (ohmed it out according to manual) and only one of the measurements was off...could be bad, so I'm trying to find a tps locally that I could just plug in to see if it starts, but I'm thinkin it's something else.

A bad TPS won't prevent it from starting, just make it run like crap.

Bill

 

[TBauer]

I did pull the codes (jumped terminal), and am getting the check engine light breifly.

Here's what else I know. Apparently, if there is no reference pulse, there will be no spark - so it appears that the signal generator is likely ok.

Talking to a local EFI guru, he suggested the 'Idle Speed Control Valve' was the likely culprate. Based on my symptoms, he had resolved a similar issue in the past by replacing it. It's a $200-$400 part!!! I think a local guy will loan me one to use in troubleshooting. I know newer FI systems use a P.I.D. for closed loop idle control, the valve on the 62's is a servo-valve that I believe plunges a stopper via a 'cork-screw' type motion, and 'dithers' back and forth to let in or stop air.

Anyone with any experience regarding the Idle Speed Control valve on a 62?

- T

 

[Moby]

I tested mine at one point, it's a simple process. Basically you just apply battery voltage to the different terminals in certain patterns and listen for it to click as it moves the plunger in and out (which controls the airflow and therefore idle speed). If you do it a bunch you can see the plunger move as well. The shop manual has the proceedure. If you don't have a shop manual you really need one for this kind of stuff.

 

[Aseif007]

Have you tested the cold start injector, could the EGR be stuck open or overly dirty. Is your fuel pressure regulator still good. I would worry about the #4 cylinder since I think it wouild take more than just bad rings to explain 0 PSI in the cylinder, and the overly noisey valve train may mean some bad stuff.

 

[TBauer]

Moby, I tested the Idle valve, it works - which is a good thing, I think...

Trouble Shooting Status:

Relay's clicking = good
Fuel pressure = good = 46psi
Fuel filter = new
Cold Start Injector = need to ohm out - Could it keep vehicle from running?
IGN = good - also replaced plugs and wires to eliminate variables
Air flow = No obstructions, mass flow valve swings freely
ECU codes = #51 = Either TPS, Air con, or Gear Selector switch
TPS = was slightly off, but as advised, engine should still run
Need to Ohm out Gear Selector switch on tranny
ISCV = plunging in and out
Tried removing vacum line from VSV valve to pressure regulator - got the sputter start ( runs on a few cyls for a few seconds then stops and won't start again).

What else???

I'm going to try and get it running with WD-40 / starting fluid / gas and get a timing light on it, maybe timing is jumping around or something...

BTW - Thanks all for posting, I do appreciate the input

 

[billmc]

I agree with the others. Ignore the 51 for now and sort out why you have 0 in #4. Then check for vacuum leaks especially at the air intake.

Bill

 

[TBauer]

Guys,

The problem with not sorting out the electronic side before you tear into the top end is significant.

Once I pull the valve cover, then likely end up needing to pull the head, I wil have had to reomve the entire intake, injection, and most of the vacum system. I'll be able to fix the mechanical zero compression issue (that's the easy part), but when I get it all back together, it still won't run

It makes alot more sense to me to know that it was running before I pulled things apart, thus it wll run after. Speaking from past experience here, it is much easier to trouble shoot that way.

These engines will run on 5 cylinders. My compression was measured cold, with only the starter motoring the engine. Not uncommon to get slightly innaccurate numbers this way, not saying cyl #4 doesn't have issues, just saying that it't not my biggest problem - Trying to Eliminate Variables.

BTW - Cold Start Injector = ohmed out to spec.

- T

 

[billmc]

These engines will run on 5 cylinders. My compression was measured cold, with only the starter motoring the engine. Not uncommon to get slightly innaccurate numbers this way, not saying cyl #4 doesn't have issues, just saying that it't not my biggest problem - Trying to Eliminate Variables.

- T

Sorry, I was simply looking at it from a troubleshooting methodology point-of-view. If you've got a solid plan already in mind, then by all means, follow it.

Bill

 

[TBauer]

No Worries Bill - I'd like to have #4 working first too, but feel that I should get the electrical beat before I tear her down.

Oh, by the way all, Code 51, which can correspond to a 'No TPS Signal' can possible not make vehicle start. When I measured the TPS resistance, the measurement that was off was IDL-E2, which is the idle curcut. I was told that you could leave the TPS unplugged, and if it started, the ECU goes into fail safe or 'limp home' (aka limp to autozone and buy a new TPS) mode. Oh, someone told me that they bought a TPS at autozone, and it was an original, Toyota Nipponenzo (sp?).

I'll let you know tomorrow what happens.

Cheers,

T