Oh Dear.. *Urgent*

[Luciano]

Would really appreciate some advice..

I drove my car 250 miles to Birmingham today, without a problem.  I then parked in an indoor car park.  When I left the car park, the following problem developed:

10% of the time -  no problem, car seems to drive ok, perhaps a little "lacking".

90% of the time, it idles very low, and also only revs to a maximum of 4000rpm at which point it begins to backfire popping and banging, making it difficult to drive about 10mph.

Any idea what this is?  I am meant to drive 250 miles home tomorrow, and am currently facing the prospect of having to leave the car in birmingham and get the train back

I\'m not in the AA

It was raining quite heavy today.

The car has done about 40,000 miles, 1994, mechanically standard.

Any help would be much appreciated.

Cheers

[scooby_si]

erm i no nothing guessing it might be in limp mode or sumin try resetting ECU, er sumin  like disconnect battery & pump brake a load of times? Anyone with knowledge wana comment.....?
Si

[fc3sPAT]

mine does that, but its because i have a exhaust that looks like its been infested with rats (basicaly lots of holes in it), on cold start it idles around 5000, when the car is hot enough, it gets back up to normal idling revs, but will be popping once in a whilewith the revs dropping a few 100s,

and when it is cold, when i stop for lights or whatever it often stalls itself, so i dont know if this is the same problem you are experiencing, by the way mine is a FC

Pat

[Luciano]

I take it you meant 500, not 5000 revs... in which case the problem sounds quite similar.  However, the low idling isn\'t really my main problem, its the fact that I can\'t take it above 4000rpm as it seems to "cut out" at this point, backfiring.  Also, in the rev range up to 4000rpm, there seems to be much less power than there should be.

The exhaust is a good point. Mine is a mazdaspeed item, and is slightly damaged underneath due to the car being low.  But the exhaust sustained no extra damage before the car began to show this problem, so I don\'t think this is the cause.

I\'m not a mechanic but I\'m *hoping* its something like spark plugs or leads??

[g11ary]

check there hose is on the map sensor.
Passenger side on fire wall small black plastic box 1x2 cm.

[fc3sPAT]

well, i am not too much of an expert, but i am hazarding a guess that it may be the ecu or your second turbo??? :confused:

if it does not deliver at around 4000revs then thats near to when your second turbo kicks in, so maybe its that that is the problem?? or it could be the ecu not allowing it to go any further for some reason?

at one point my car wouldnt go over 0.3bar of boost because when i fitted the boost controller i didnt remove the standard boost solnoid valve, so i guessed that the ecu limited me to 0.3bar as a precautionary measure???

my point is, maybe there is something wrong witht the second turbo and the ecu has picked that up therefore holding the car back?? but the popping and backfiring sounds like a rusty exhaust to me,

[Luciano]

I\'ve just come back from checking it again - it now does it 100% of the time, and cuts out as follows:

4000rpm in 1st gear
c.3000rpm in 2nd gear
and lower in 3rd

So it does seem as though the ECU is limiting boost..?  Anyway I\'ll check the hose is on the map sensor and report back

Thanks a lot for your replies so far, its really appreciated!!

[Rixio]

I have the same problem i was just about to post a new thread about it aswell!!!!...i just managed to start my car finally this evening, after 4 weeks of sitting in the drive. it idles and revs fine but when in gear and actually driving it cuts out at 3k-4k revs and backfires/heavy poping like gunshots scares shit outa people including me!! sounds really dangerous to the engine i thought it might be the restricter or something, i reset the ecu took the battery off etc. im using a 20amp fuse instead of a 30amp in the small fuse box next to the battery ill check which one in the morning, because when it was stolen the thieves pulled all the fuses out and no1 had any 40amp fuses today when i went to buy one. but its the same as yours luciano as soon as you put ur foot down it fires and pops but doesnt move! if you mildly accl then you can go through the rev range but u put ur foot down half way and it fires/pops!!! Gary what were u refering to? the fuse box i mentioned? could it be the fuse? ill get the propper fuses on monday see if it makes any difference. ill try resetting and changing fuses around etc tmrw morning.

"check hose is on map sensor" plz can ou take a pic so i know what to look for...


Rixio:wave

[sdminus]

Use the diagnostic socket bud. i cant remember which pins it is but you can put a led between em and if you count the flashes you can relate it to a fault code. there is a list somewhere on the net. i can get one if need be but not straight away
scott
somebody on here must know

[Luciano]

I\'ve checked the hose on the MAP sensor and its connected correctly.

Rixio, if you need a picture go to http://www.iluvmyrx7.com/ select Gen 3 Manual and then Fuel and Emmission control systems.  Its on page F167.

I\'ll have to read the fault code tomorrow.  I\'m a bit worried that if I don\'t get it sorted by tomorrow afternoon I\'ll have to leave it here in Birmingham and catch the train back to newcastle.  

[sdminus]

I know this dont help much mate but tow it home. dont leave it there.  I think there should be a calling all rex owners in bham help post...
scott

[Luciano]

Its not so bad leaving it in Birmingham, my girlfriend lives there so it should be relatively safe.  

The annoying thing is that it\'ll take longer and be more difficult to repair the problem when the car is so far from where I live!

Its life I guess.  I\'ll read the fault code tomorrow and see if that helps.  

Incidentally, if the engine management light isn\'t on, shouldn\'t that indicate that the ECU hasn\'t got any fault codes stored inside?

[Rixio]

the ecu light comes on only when its registered a fault and logged it yes so theres no prob there...i actually just remebered that my abs light is on aswell dono why any ideas??

rixio:wave

[sdminus]

My last attempt.
have you tried letting the car fully warm up before moving it. if the engine temp sensor is dead it will go in to limp mode but you might stand a chance if it warms up fully first.. dunno for defo just trying to give you ideas. sorry mate
scott:mad:

[kbareham]

Not sure whether it\'s the same problem, but might be worth considering. Mine has an intermittent problem that\'s a little like this. It will start up normally, usual idle, but cuts out as you apply more throttle. I haven\'t pushed it too far past the cut out point so I don\'t know whether it backfires under harder throttle. If you have  a boost guage, it runs fine to about 200 mm/hg but above that it goes slightly "fluffy" and then cuts out. The ECU light does not come on.
I\'m still chasing the fault, but it goes away when I try to trace it.
Simple way to get it to run again - remove one hose from the pressure tank (under the strut brace) to vent the pressure. Remove the hoses from the small green and white check valves under the mainfold next to the pressure tank to vent the vacuum. Put it back together. Important! - now leave it for 4 hours. After that it normally runs perfectly again for a few weeks before breaking again.
I think that mine is due to a sticking solonoid in the solonoid pack under the manifold because the vacuum to the charge control valve drops when the fault appears. Unfortunately, taking it apart  fixes it, so I haven\'t found which one it is yet!

Rgds
Keith