Anyone have a problem with weak injector pulse?

[GBGN1]

My we4 in sig. Wants to start but doesnt. Engine will turn over with no pulse and then 5-10 revolutions and then pulse will start along with engine wanting to start but doesnt.Has good spark . Pump prime,Cam sensor good and timed correctly. Last time I checked voltage at cam sensor was good and had 7 volts at blue wire. TR6 now has no codes. Its weird. Idea's?

 

[aminga]

sounds like the fuel pump relay has gone south and it's starting off the backup circuit.

The ECM fires the injectors by grounding them so there's really no such thing as a weak injector pulse. They either fire or don't

 

[GBGN1]

Well I just tryed it again. Now no pulse at all. Half the time the Fuel prime doesnt come on. real random. There is bat voltage at the injector harness and all connections. I jumped the hotwire fuel pump relay and the fuel pump relay with no luck.

 

[aminga]

Check engine light come on KOEO?

 

[reddog3.8]

Check the ground wires on the back of the passengers side head. Bad or loose ground on the wires will cause no injector pulse and a no check engine light


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[GBGN1]

Ok I will, couldn't remember if I had a check engine light with fast classic or not but thought I did.

 

[GBGN1]

Check engine light come on KOEO?

No check engine light at all. Just cannt remember if it worked after the fast classic install but I think it did.

 

[aminga]

No check engine light at all. Just cannt remember if it worked after the fast classic install but I think it did.

Didn't see that it was fast. Nevermind

 

[Chuck Leeper]

Don't recall a CEL w/ the old FAST I had...

 

[TurboBob]

how about hooking up a laptop to the fast and seeing what it thinks is going on..

 

[GBGN1]

The laptops always on it. Only thing I though looked weird was where it says rpm. It is zero when turning motor over. but tach (s) are
Moving . Maybe normal. What should I be looking at with no injector pulse?
Thanks

 

[dynoman]

Do you have a NOID light tester ? Are you positive you have fuel pressure at the rail ? Hook up the tester & watch it while cranking .

 

[GBGN1]

Yes I have a noid light on it right now .no pulse. When it primes yes it has pressure at the rail. But only primes randomly

 

[RmvBfrFlght]

Check the fusible link at the battery. That supplies power to the ECM and is a known weak point. Age has taken its toll on them.

RemoveBeforeFlight

 

[GBGN1]

Yeah no the fuse able link is good.
Plugged a stock ECM still no - pulse so I can cross that off my list.

 

[Gmoney]

Have you done any work to the ignition module lately!! When I purchased my car from the original owner I had the same symtoms!! The old guy crossed a couple of wires in the ignition module and was causing no pulse weak pulse some pulse!! I corrected the wires and problem solved!! Good Luck

 

[Gmoney]

Just seen your TR6!! MY BAD

 

[Chuck Leeper]

Foggy memory here...{at my age, everything is foggy}
AIRC.
Unit has 2 pwr inputs, full time and key.
If the full time is good, and KOEO gets prime, but start position gets nothing, I'd look at the key power being flaky.
W/O tach signal to the unit, no start is a for sure. {what's rpm to start set at? AIRC mine was 400.}
Is the tach wired in w/ the FAST circuitry? If not, and the tach works, I'd look at the tach wiring to the unit. If this is the case, plugging the stock ecm in, will not get a tach signal, either.
Have you changed any of the tune parameters?

Maybe Cal, or the other gurus, will chime in and we'll all get some "education"..

 

[GBGN1]

Yes should start at 400. Tach is attached to stock wiring harness not fast. Haven't touched calibrations before or after problem. I'll look at it soon. Over 100 deg all week!!

 

[Chuck Leeper]

Over 100 deg all week!!

It's 97* here, in the shade! Sure am glad the shop ac is working....

What's with the "dumb" rating on my post?