Need engine diagnosis help

[G NASTY]

After a WOT run my car made a popping sound about redline then stalled and died. Iam going crazy trying to figure out the problem. The car now cranks but will not turn over. I checked all the fuses and there fine. Iam getting no spark at the coil pack so iam assuming it might be the igniter module or the cam sensor. Any ideas before I buy both and hope for the best?

 

[turbojd]

I would check the crank sensor, and ignition module. When I change the ignition module I like to replace the coil pack with it.

 

[G NASTY]

any more ideas?

 

[kingots2004]

how much boost? what fuel pump? got alky? sure its not firing?

 

[G NASTY]

completly stock. No alky. When I take the plug wire off iam not getting any spark

 

[kingots2004]

check what turbojd said not sure how the car cranks but wont turn over? i think you mean the opposite also the cam sesor has to work for the car to start but not to run after it starts.im thinking sometimes the rotor under the cap breaks and it wont sync up with the crank sensor so look at that also

 

[G NASTY]

The car sounds like it's going to start but never starts. I guess it's not getting spark. It only cranks when iam holding the key down.

 

[Just a Six??]

As mentioned Check the cam sensor ring to see if it came loose. Happens 20% of the time. next its crank sensor.

 

[G NASTY]

how do i get to the cam sensor ring?

 

[FreeBoost]

Crank sensor!!!

 

[TurboDave]

As mentioned Check the cam sensor ring to see if it came loose. Happens 20% of the time. next its crank sensor.

I might be mistaken, but I wouldn't think a cam sensor problem would have caused the car to pop and die. Crank sensor certainly would.
The reason I say that is that if your car is running, and you unplug the cam sensor, it will continue to run (in batch fire mode). Wont restart after you shut if though.

This just happened to my Son-In-Law last night with his LC7 powered Mazda. I have to work today, but left him at home to trouble shoot the issue. Will let you know what he finds. Told him to check the crank sensor, ignition module, (and just in case, also check cam sensor ring). Fortunately I have plenty of spare parts down there in the garage for him to try.

 

[machinegun]

Either using a NOID light or just a test light, see if you are getting injector fire. If not look more at the crank sensor. You may also want to find someone close to borrow a CP and IM.

 

[turbot990]

take off the cam sensor car buy removing 2 small philip screws put your hand on the metal relutor ring and try to turn it if you can there is your problem rjc.racing sells a repair kit.or some of the other vendors on the board.

 

[TurboDave]

I was wrong!! Imagine that.:redface:

We pulled the cam sensor cap and found the reluctor ring spinning. Broken tab.

 

[turbot990]

BINGO YOU ARE A WINNER and you are welcome merry x mas i work on these cars alot glad i could help.HESS RACING.

 

[TurboDave]

BINGO YOU ARE A WINNER and you are welcome merry x mas i work on these cars alot glad i could help.HESS RACING.

As do I, but I hadn't had this particular problem bite me yet in the last 22 years. Crank sensor, yes. Not this one.

So anyway, John's car is running now. Hopefully trans damm will be as lucky.

 

[turbot990]

I just want to say 1 i thank Mr. Kent Rudbeck for getting me into these cars and for the great imformation he has shared with me threw the years there are many great techs on this board that has helped me in the past im just glad i can return the favor.merry x mas guys.

 

[Just a Six??]

I might be mistaken, but I wouldn't think a cam sensor problem would have caused the car to pop and die. Crank sensor certainly would.
The reason I say that is that if your car is running, and you unplug the cam sensor, it will continue to run (in batch fire mode). Wont restart after you shut if though.

This just happened to my Son-In-Law last night with his LC7 powered Mazda. I have to work today, but left him at home to trouble shoot the issue. Will let you know what he finds. Told him to check the crank sensor, ignition module, (and just in case, also check cam sensor ring). Fortunately I have plenty of spare parts down there in the garage for him to try.

You may be correct but from what I recall years ago I was driving down the street & the car started acting all screwed up with farting & like it had no gas or something. I pulled to the side & got around a corner & it died & was towed back. Thats when I found the broken tab on the ring. Thats why it always comes to mind for me. This was before I had the net & it was a PITA to find that one as my mechanic & I had never heard of this before. I was allowed to work on my car in his shop as I knew the car well & he is an electrical specialist. Sure glad we have these boards as its SO much easier to diagnose the cars!

 

[TurboDave]

Like I said somewhere else, I've never had this type of failure on any of my T/R's. I mistakenly surmised that because you could unplug the cam sensor with the engine running and it would not die or run bad (just switches to batch fire mode), I naturally assumed when the tab breaks that it wouldn't kill the car.

22+ years working on these things and there's still something to learn occasionally. :biggrin:

Anyway we got John's Mazda fired and running with one of my spare cam sensors.

I keep waiting for trans damm to come back into the thread and let us know what he found.

 

[whitehot1]

+ 1 on never having a cam sensor tab breaking in the 20 years of messing with these cars.

I vote for the crank sensor being the problem for the starter of this thread but i would remove the cap from the cam sensor and have a look there since it only takes a couple of minutes to do it.