M104-AMG

iTrader: (8)

We replaced the engine and wiring-harness, and while the car turns-over, we get no combustion.

We have done the following:

1) checked all relays and fuses;
2) checked for spark;
3) primed fuel-pump & checked fuel-pump relay;
4) reset ECU three-times;
5) replaced spark-plugs after cranking for 4-times;
6) checked ignitor and fuel-pump resistor;

We ASSUME the crank-angle sensors (CAS) are working since we get spark- do I need to remove the CAS and check them ?

We don't think we hear via a stethoscope the injectors, however, they were recently serviced by RC-engineering.

The factory manual shows a resistance of apprx. 30-ohms per injector, and I'm getting 330-ohms per injector when measuring between the positive voltage supply to the injectors (120-amp fuse) and the appropriate wiring harness pins (LG/B; LG/R; etc.).

Can I accurately test the resistance of the injectors this way, or do I need to physically disconnect the wiring harness from the injectors and re-measure ?

Any other ideas of why no combustion ?

Thanks,
:-( neil

ebb

I have been through this, go through the basics again. You know you have spark, good. Check fuel pressure, if you have that then check your injectors with 12v make sure they are fine. Check signal to injectors, are you getting any codes? what ecu are you using? If you are using the stock ecu it will tell you if any of the injectors does not have continuity.

If the spark is occuring at all the wrong times then it may not fire, I have done this also, check your coils to see they are all hooked up correctly. Have you pulled the plugs? possible flooding?

theoretically if you have fuel, spark, and compression you are good to go. Do you have compression?

mad_7tist

the injetor needs to be ohmed by itself. for what that test is worth, it only shows that the coil is not open or shorted not if the pintle moves. how did the plug look when you changed them? what ecu? and yes have you verified that you have compression?

M104-AMG

iTrader: (8)

Yes, we have compression.

I have both a stock ECU and a M2 Stage III.

Plugs pulled and no flooding. Seems like the injector aren't working . . .

How do get the stock ECU to test injector continuity and how do I retrieve them ?

How do I check signal to injectors ?

:-) neil

mad_7tist

you can get a noid light from a store that plugs into the harness and flashes. but if you have a good , snap on or mac, high impedence test light you can pull the harness off the injector, put the clip on the batt + stick the light in the ground side of the harness and turn the engine over. the light should strobe. then put the clip on the - side of the batt and look for power in the other terminal of the connector. are you sure you have fuel pressure? the pump turns on etc??? the check engine light comes on with the key in the on position right?

DaleClark

iTrader: (55)

The stock ECU should store a code if the injector isn't hooked up. Pull the ECU codes and see what you get.

Is the engine a fresh reman or rebuild, or is it a used engine? I seem to remember something about you having a spare engine around. Either way, there's a jillion little things that can cause the problem. Not to mention new and used engines sometimes don't feel like cranking up easily - you have to get some oil in the combustion chamber, crank on it, charge batteries back up, you name it.

Just keep at it - verify that everything is the way it should be. It's frustrating when you get to this point, and it's typically some VERY small detail that was missed somewhere.

Good luck!
Dale

dubulup

hit the injectors with 12V...if they click they are fine.

I had injectors stick after cleaning at RC...

DamonB

Looks like you have checked everything. Since you're getting spark I wouldn't bother checking anything else in the ignition. In fact I wouldn't bother checking anything else at all until I was CERTAIN there is fuel coming through the injectors.

If the plugs didn't get wet then you are most likely right about the injectors. They should audibly click when the engine is turning over. I know if I stand over the LIM I can hear mine even with the engine running.

dubulup

Mine are also pretty loud...no FPD and aftermarket FPR, don't know if that matters, but I did notice they were louder after the build.

M104-AMG

iTrader: (8)

So if the injectors "stick" how can I get them to unstick ?

BTW: there were just cleaned by RC Engineering.

:-) neil

dubulup

mine were "just" cleaned also...it's the cleaning solution that can make it stick, if it sits for some time with out firing. RC will fix the problem for free, if this is the case.

M104-AMG

iTrader: (8)

I applied 12V to the injector and heard them click. Car started up, but died.

Seems like the primary injectors are sticking. Other than pulling them out, can I just apply 12V to them over-and-over to get them unstuck ?

:-) neil

dubulup

why do you think they are sticking if you can hear it clicking? clicking is indication they are not sticking.

M104-AMG

iTrader: (8)

Sometimes the primaries injectors will "click" when 12VDC applied, sometimes not.

I think that's why it won't stay started.

So, how do I get them to unstick ? Just cycle them with 12VDC a couple times ?

:-( neil

DaleClark

iTrader: (55)

Worth trying - I know it won't hurt them.

I'd also double-check that you don't have the fuel lines on backwards - that's easy to do and causes all kinds of fuel system weirdness.

Keep at it man!

Dale

dubulup

make sure it's not your connection making them intermittent

M104-AMG

iTrader: (8)

I called RC Engineering, and he said the new rubber pintles may be too tight, so to take the injector out and gently push them in-n-out a couple of times.

I'll also check the continuity of the wires and clean-up the connectors while I'm at it.

Here's hoping. . .

:-) neil

M104-AMG

iTrader: (8)

Please verify:

The three pipes when facing them and going from left-to-right should go as follows:

(1) from fuel-pump (this hose gets stiff as it builds up pressure)
(2) to fuel-tank (return)

The pipe on "top" of the triangle arrangement is for the charcoal cannister.

Thanks,
:-) neil

M104-AMG

iTrader: (8)

I must have cycled the primary injectors with 12VDC about 50-times, but it finally is free and the engine started right up and idles fine.

I let it idle for 20-minutes to burn away all the ATF I added. Then took it for a 10-mile drive with RPM's upto 7000 RPM.

Unfortunately, I now have a "CHECK ENGINE" light, and resetting the ECU (remove battery negative for 20+ minutes), doesn't seem to help.

How can I retrieve the codes without a scanner ?

TIA,
:-) neil

Mahjik

iTrader: (1)

http://www.scuderiaciriani.com/rx7/engine_codes.html

M104-AMG

iTrader: (8)

Thanks for everyone's help.

I retrieved the code (#9- water thermosensor) and did the tests and it was the sensor itself.

Changed it out (PITA, had to remove the alternator & smog-pump), and all is well.

We're autocrossing this Sunday!

:-) neil

M104-AMG

iTrader: (8)

Placed 1st in SCCA Super Stock today. 2nd was a Porsche 911 (1995). I beat him by 3-seconds.

Again, thanks to all.

:-) neil

dubulup

Fawking Right Man!!!

DaleClark

iTrader: (55)

Awesome! Glad you got it all cleared up and it was something simple . I'll have to remember that trick on the injectors - that's good to know!

Good work, Neil!

Dale

M104-AMG

iTrader: (8)

Actually, it was a 2003 Porsche 911, not 1995. Makes me feel even better, esp. since I have the Touring suspension.

Can't wait for my Tri-point front swaybar, and some double-adjustable shocks . . .

:-) neil