Strange Problem..Electrical?..Other?

[Wav]

Hey Guys,

I'm really stumped, and I'm never usually stumped so I think this is a strange one. Basically the Stealth will not start, even after a fresh engine with 7bar of compression on each rotor face when cold and not run in!

Here is the story so far, I'll try to keep this as short as possible :Typing

Last month the Stealth (FD) just wouldn't start after washing her. Car combusts when you turn key, but as soon you apply throttle it simply cut out.

Checked for spark, resistance of coils, CAS, injectors, flooding, fuel pressure was 43psi base etc and they were all fine.

Compression was very low, 5bar on rear rotor and 4 bar on front rotor from cold(engine has done 65k miles), tried tow starting and it combusts when in gear, but didn't sound "loud" as it would and died as soon as put clutch in.

Anyway we rebuilt another engine as it needed doing anyway and dropped it in. Car started first time and with a little help of throttle it eventually stabilised and sat idling on axle stands for 30mins up to full temps, at this point engine sounded fine(exhaust note etc) and rev'd freely.

Put all the intercooler pipes back on and took it off axle stands and started it again, went to reverse it out of the garage and it cut out. Then it started doing the same thing again with the other engine, started but cut out with any throttle at all!

Last thing we did that night was change the map sensor for another one and woots got the car started with 1/4 throttle while turning key. It ran really rough, engine shaking a little and the exhuast note is really subdued, the wideband is saying it is very lean above 16.5afr at idle and after that we drove round the block and put it back to rest.....as it was late, fuel pressure was 40psi base with a new aeromotive fpr.

It now doesn't start at all, you can hear it trying to fire up and it definitely ISN'T flooded and we did a comp test last night and all is well with new engine. As far as I can see there are no air leaks or cause for air leaks.

So if anyone can shed any light please post ahead. Any ideas welcome, however dumb you may think they are, i'll just post up in reply saying whether I've already tried it or not.

Ta,

Paul:)

[dandan]

*prepare yourself for dumb suggestions*

From what you said I can only say it must be something that was NOT changed in the engine swap, so i'm thinking management, or any ancillaries that were used for both engines...
Might not be a solution you must be able to narrow it down to certain items.

Thats all you will get out of me! :)

[davegttph1]

Again, might sound simple. Dont think youve mentioned it, most cars have them and Im gonna sound stupid if the rex doesnt have them but the fuel filter???? just a thought.

[efiniste]

Have you tried a different coil pack on it Paul? Sounds like the spark may be breaking down.

[Gman]

Throttle stuck wide open as if pedal was to the floor?

[nikp]

I thought a Spark problem - getting weaker the more throttle thats applied. Or getting weak when the throttle is applied!

[ro284]

With all that turning over, you would expect it to be flooded by now, is the fuel pump playing up?any fuel smell from exhaust?
Good luck Bob

[Wav]

Ok, as i said before there is no such thing as a dumb question, as I could have missed something simple. so fire away.

1. I have tried a std ecu in place of the apexi, so that has been done.

2.fuel filter is brand new and i'm getting 40psi base pressure on the fpr gauge, so there is definitely flow and pressure within the fuel rail.

3. The car isn't flooded as the last thing i did was take the leading the plugs out to comp test the engine. The plugs did smell of fuel, but they were not soaked as they would be if it were flooded. Eitherway I wire brushed the plugs, span out all the excess fuel in chambers, and heated plugs with blow torch before putting them back in. Car still behaves exactly the same. Fuel pump is an option, but then you would/should see any pressure drop on the fpr pressure gauge if the pump is at fault.

4. throttle pedal is not stuck down nor is it jammed in any other position, it moves freely at the throttle body.

5. A weak spark is the next step, funny you should mention coil pack as i have just taken the one off the breaking car to try, fingers crossed that will sort it, although the old coil pack was within spec re the mazda workshop manual.

Keep em coming.

Ta,

Paul:)

[G@NDY]

Have you tried kicking it?

[Wav]

Have you tried kicking it?

Yes repeatedly, after that didn't work I set fire to your GReddy SMIC as sacrifice to make my car work again :flamed ;)

Paul

[G@NDY]

:eek :eek Thats not very nice paul. I guess i will take all that nice crisp cashola that was coming your way, and go and blow it all on gin, strippers and squirty cheese. :p

[Wav]

:eek :eek Thats not very nice paul. I guess i will take all that nice crisp cashola that was coming your way, and go and blow it all on gin, strippers and squirty cheese. :p

Now that sounds like a good night out :Ladys-man :Thumbs-up

Paul;)

[zymark]

Is the fuel pump uprated? I ask because I recently had an uprated pump fitted and found it really difficult to start my FD. It turned out that although I had 1/8-1/6 of a tank of fuel the pump was pulling so much that it was cavitating and drawing vapor/air through the lines. I read about the problem on one of the forums can't remember where. Anyway it was cured by putting more fuel in the tank.

Strange but true had me worried I had killed the car for a good two days

[Freddy]

Have you tried kicking it?


I reckon Bab'z hammer will do the trick. ;)

[Wav]

Is the fuel pump uprated? I ask because I recently had an uprated pump fitted and found it really difficult to start my FD. It turned out that although I had 1/8-1/6 of a tank of fuel the pump was pulling so much that it was cavitating and drawing vapor/air through the lines. I read about the problem on one of the forums can't remember where. Anyway it was cured by putting more fuel in the tank.

Strange but true had me worried I had killed the car for a good two days


Yeah it is a supra tt pump so should be fine, there is also half a tank of fuel in the car. I will check the connections of the pump though, you never know they could be loose.

Cheers,

Paul

[bnaellis]

You said the car is not flooding from continues cranking, so it sounds mor elike a fuel related issue than electrical. The lid that covers the fule pump make sure the ground has a good connection to it and it's not rusty.
Simple way to check pump operation and that fuel is being supplied, is pull off the fuel line from the rail just under the greddy elbow get a bottle andf get someone to crank. If no fuel enters the bottle it's obvious if fuel does enter, you have atleats eliminated a few things instantly.
You easily test the spark from HT lead to eliminate the igniter, coil pack and leads. Check the egi fuse, pull it out and check the terminals where it plugs in.
Infact I now remember a similar issue a few years ago on one and one of the ht leads had green gunge on the inside terminal from moisture.

[Wav]

You said the car is not flooding from continues cranking, so it sounds mor elike a fuel related issue than electrical. The lid that covers the fule pump make sure the ground has a good connection to it and it's not rusty.
Simple way to check pump operation and that fuel is being supplied, is pull off the fuel line from the rail just under the greddy elbow get a bottle andf get someone to crank. If no fuel enters the bottle it's obvious if fuel does enter, you have atleats eliminated a few things instantly.
You easily test the spark from HT lead to eliminate the igniter, coil pack and leads. Check the egi fuse, pull it out and check the terminals where it plugs in.
Infact I now remember a similar issue a few years ago on one and one of the ht leads had green gunge on the inside terminal from moisture.

Thanks for that Brian.

There was fuel in the chambers, but perhaps not as much as you'd expect. Anyway I have now removed and tested the fuel pump( it appears fine with the ground wire intact), hard wired the fuel pump "speed" relay on, so that the pump sees full power all the time and the the car is definietly getting more fuel in and when you take the plugs out they are soaking with fuel, obviously the car stil isn't starting. Although it did go briefly before it stalled again, still running rough.

I have now changed the igniter and coil pack along with a different set of leads and still no change :( Am going to do some serious de-flooding just in case this is now stopping it from starting.

If this doesn't sort it then the only thing i can thing of is if the timing is out so the plugs are firing at the wrong time :3Confused

It is all very strange and very annoying at the same time,

Ta,

Paul

[7ForLife]

surley when you give it throttle more air goes in. if it doesn't add more fuel it will be lean and if too lean it will cut out. thats only going to be the case if you have a strong spark. more air could blow the spark out. but think you have ruled this out. or as you say the timing could be out. so there could be a problem with one of the crank angle sensors.

The Oracal (workshop manual) suggests

fuel pressure reg
primary injectors
throttle sensor
crank angle sensors
ignition timing
ecu

and a bunch of other stuff you have tried

[moakesr]

Hi Paul,

Given that it did run, and now will not, have you checked that the fuel tank vent is working? You could be pulling fuel against a vacuum if the vent were blocked?

Cheers,

Richard

[nikp]

Surely thats ^ unlikey as he's getting good fuel pressure and fuel delivery.

[Wav]

Thanks guys for all your replies.

Hope you will be happy to hear that she has started again :3gears-rh

We got it started by putting in a std, well re-a, ecu, 7 rated plugs in the leading holes and by deflooding the car PROPERLY. I think it was a combination of a dodgy map sensor plug (wasn't connecting properly) and the pfc throwing it's toys out of the pram! :rolleyes: and I also think the ignitor did something also, but car was so flooded that the difference was not seen at the time.

After 40 or so miles I've now put back in the apexi and it is running sweet again, just gotta run it in now. Glad the apexi isn't knackered, the std ecu didn't like the 1600cc secondaries ;)

Cheers,

Paul

P.S. anyone know why my rear lights, dash lights and side lights are no longer working, but my main front lights are? we're not going to get many miles down if we can't drive it at night:(

[Wav]

P.S. anyone know why my rear lights, dash lights and side lights are no longer working, but my main front lights are? we're not going to get many miles down if we can't drive it at night:(

Sorted now, was the TNS relay at the front of the car, must of got soaked along with the other relays when the car got washed, which I'm sure the water caused all these non starting issues in the first place:2Confused ;)

[moakesr]

Hi Paul,

Glad to hear you got it sorted, should be in nice fettle for some track action when it's run in.

Cheers,

Richard