legacycentral bbs

Reason: Former Open Class rally car needs to go to Open Light, so NA engine installed.

Whats been done:
-- Swapped cam and crank sensors on ECU connectors via this diagram: http://www.surrealmirage.com/vrg3/ecupins/
-- 94SS Legacy with a 91 Legacy L engine with Delta Cams
-- Using Turbo engine harness on the NA Intake

Problem:
-- Car will not start
-- Cranks over, gets spark, has fuel pressure
-- When ignition is turned on, very random and intermittent clicks from the fuel pump as well as the fuel injectors clicking like crazy and in a very random pattern.

Time needed to fix?:
-- None. Car needs to be on a trailer and ready to roll by Wednesday night, lots of other stuff that needs to be done to the car now.


Any ideas? Does anyone have a picture of the Cam/Crank sensor swap on the wiring side? One thing that was noticed when doing the rewiring was that the wire colors seemed to be strange. Black went on White, and white went on black. We thought that was strange after it wouldn't fire the first time, so tried swapping it to black-black and white-white. Still the exact same issue.

Please help!

Probably a stupid question but do you have the na MAF or the turbo MAF? Don't know if that would cause a problem but just an idea. I did the opposite swap but don't remember the wiring colors. I just swapped the crank angle power, signal, and ground with the cam angle wires.

NA MAF. Although I could try it with the Turbo MAF.

*EDIT* After doing a lot of reading, seems the Automatic and Manual MAF's aren't the same. The parts car I bought was originally an automatic, but the owner did a manual swap, but had some seriously hacked up wiring leading to the MAF. Makes me think that he used an Automatic MAF still, but adjusted it to work with the manual swap on the harness side. Going to take my old turbo MT MAF and put that in.

I don't believe you can just plug the 94 engine's intake manifold harness into your 91. They switched the pinouts between the 1992 and 1992 model years. You're probably shorting out a bunch of things and forcing the ECU to keep resetting to avoid cooking itself. Unplug it right away!

Use your stock 91 engine harness and add new wires for the sensors on the passenger side strut tower. You only really need to run four wires all the way to the ECU -- the ground-side wires for the boost control solenoid and the pressure exhange solenoid, and the pressure sensor power supply and signal. The other sides of the solenoids can be spliced into the +12v supply to the purge solenoid (or whatever's convenient) and the pressure sensor can be grounded to the main ground on the intake manifold.

The cam and crank angle sensors do use opposite wire colors -- the crank sensor's positive wire is black and the negative wire is white, and the cam sensor is just the opposite. So you had those pins right the first time.

Also, if your car is a manual, the NA and turbo MAF sensors are the same. If it's an automatic, though, you definitely have to swap MAF sensors.

vrg3 wrote:I don't believe you can just plug the 94 engine's intake manifold harness into your 91. They switched the pinouts between the 1992 and 1992 model years. You're probably shorting out a bunch of things and forcing the ECU to keep resetting to avoid cooking itself. Unplug it right away!

The car is originally a 94. The engine was a 91. The engine harness plugs were not the same on the 91 as they are on the 94. It was Square-Square-Circle (91), verses Square-Square-Square (94). So I used the 94 engine harness on the 91 Intake/Shortblock. I switched the turbo coolant crossover pipe so that I didn't have to lengthen the coolant temperature sensor, and using the turbo throttle body.

vrg3 wrote:Use your stock 91 engine harness and add new wires for the sensors on the passenger side strut tower. You only really need to run four wires all the way to the ECU -- the ground-side wires for the boost control solenoid and the pressure exhange solenoid, and the pressure sensor power supply and signal. The other sides of the solenoids can be spliced into the +12v supply to the purge solenoid (or whatever's convenient) and the pressure sensor can be grounded to the main ground on the intake manifold.

I am kind of confused. Are you thinking that I am going from an NA 1991 car and trying to put in a turbo engine from a 1994? It is the other way. I know, kind of opposite from what everyone else does around here.

vrg3 wrote:Also, if your car is a manual, the NA and turbo MAF sensors are the same. If it's an automatic, though, you definitely have to swap MAF sensors.

Came to that realization while you were typing your post probably. Having my friend check the sensors right now, as I am at work. But it is very possible since the parts car (91 Legacy L) was originally an automatic, but the owner did a manual swap. And there was some seriously hacked up wiring going on near the MAF.

Is there a possibility I need to do something else to the ECU if it is an Automatic ECU (assuming, not 100% sure, previous owner might have swapped ECUs) that would keep it from starting on an manual car?

Thank you all for your help so far! Every little bit of information helps!

Okay, turbo ECU I have is hitachi made, and using a hitachi MAF from a manual car.

NA ECU is Autecs, and an Autecs MAF, but from an automatic car (originally).

*EDIT* part number searching confirms that the ECU being used right now is from a 1994 NA 5MT despite coming from a 1991 car that was originally an automatic. Does Autecs make a manual and automatic MAF?

Oh, I'm sorry! I misread and didn't understand that you were converting in the other direction. My mistake.

So you're using all the stock wiring on the 94 turbo car, even the wiring on the intake manifold, and just switched the cam and crank sensor wires at the ECU. That should be right.

There is no such thing as an "automatic MAF" or a "manual MAF." There are just HItachi MAF sensors and Autecs/JECS MAF sensors.

A Hitachi ECU needs a Hitachi MAF sensor, and an Autecs or JECS ECU needs an Autecs or JECS MAF sensor.

All 1990-1991 manual models have Hitachi engine management.
All turbo models have Hitachi engine management.
All other models have JECS or Autecs engine management.

So yes, you should be using the black plastic MAF sensor from the 94 donor car.

94 ECUs were different for manual and automatic transmissions, but that shouldn't prevent the car from starting.

In any case, the random and intermittent clicking sounds like a power supply problem, which is why I had first suspected something was being shorted out by incorrect wiring. It sounds like your wiring is all correct, but it still seems like a short or a bad connection causing a faulty power supply to the ECU.

Dumb question -- is it possible your battery terminals aren't tight?

I'll second Vikash's comment, if you're running the 94 JECS ECU, you need to be running the black plastic MAF sensor.

Did you swap just the cam/crank sensor positive pins at the ECU or did you swap the positive & negative pins?

We swapped the positive, negative, and shield pins.

Have you tried running the JECS Maf yet? If so did that work?

If the MAF doesn't change things, then yeah check the battery connections and for kicks....you may want to see if any codes are stored in the ECU.

So, after doing a bunch of more reading (god I love this site, such a good source of info) I think I might have done the TB wrong. I don't ever recall trying to line up the crankshaft sprocket tick marks on the rear of it, I think I might have been trying to do it via the arrow or a tick mark on the front of the sprocket. The cam sprockets I know for sure are lined up correctly.

So, would this cause the issue (well, I mean, duh)? And would the conflicting cam/crankshaft signals be causing the ECU to get confused and make the injectors click like crazy?

Once I leave work, and get to the garage I will pull off the crank pulley and covers to check first.

I don't believe it could cause the random intermittent clicking, certainly not from the fuel pump.

You can do a simple timing belt check by doing a quick compression test.

Fantastic, that'll be a good way to test it without tearing it down. So guessing if I have almost zero compression in a cylinder because the valves are partially open during the compression stroke that it's a bad TB job? I did test compression on the "new" engine going into the car and it was strong even compression across all the cylinders.

Yes, that's right. Test all the cylinders, too, just in case. It's good that you did a compression test before -- you can just compare your results.

Sure enough, it was the timing belt. Redid it the proper way and it fired right up. Using an Autecs ECU and Autecs MAF, cam and crank signal wires swapped back to the right way. Runs great!

Thank you all for your help!

Excellent!

Glad to hear you got it figured out!

Good thing for old school non interference engines. If you had a newer engine in there interference, you would likely be pulling heads and spending money to fix the belt issue.

I like old scoobies that are non interference.

That's exactly why I went with a 2.2L for my rally car rather than a 2.5. Better reliability, non-interference heads, and cheap. The few extra ponies in a 2.5 isn't worth the headgasket issues, especially when going WOT for over 150 miles over a weekend. Even with a 3.9 turbo trans still in the car, the engine pulls way harder than my deturboed 2.2T ever did.