What have I done to my car?

[toxo]

Something is not right with my engine. I'm leaning towards my cambelt having slipped a tooth on the intake cam, but am open to any other suggestions!

Here are the symptoms:

Car has lost 25bhp in less than a month (2 different runs at SRR, similar weather conditions).
Sounds like a light misfire on idle
Exhaust is noticeably louder than it used to be
Flames on overrun on the dyno - car has not got a very free flowing exhaust so has never flamed before!
When cold, if I build some revs up slowly and then put my foot on the clutch, the revs drop to around 400rpm and the car nearly stalls!
When warm idling ~100rpm lower than normal
Starter motor turns engine over much easier than it used to - car starts quicker but the noise from the motor is also higher pitched suggesting it's got less resistance to turning the engine over.

[Marf]

Sounds like it could be a slipped cam belt.

Might be worth doing a compression and leakdown test too.

[deano 1]

sounds like cambelt 2 me as well mate get it checked mate worth checkin your rocker cover screws they may be lose with u mistakin louder exhaust its more likely louder engine bein thugh there at the back of our heads good luck bud

[bobhatton]

If you had one of the clear cam covers you could see if the belt and timing was off, but only for Rev 1 & 2


Bob

[toxo]

lol!

I got Rogue to stick a timing light on it yesterday and Matt said the ignition timing was at about 11 degrees so within spec more or less...

I am going to give it a good service and see what difference that makes, but I can't do that until next month, so my next step is to pop the dizzy cap off and see if it's got anything wrong with it. I also have my suspicions about both the ignitor and the TPS (for an unrelated reason) so they will get checked out too.

[Driftlimits Performance]

yo John pop in I'll check the static timing for ya

[greeny]

lol!

I got Rogue to stick a timing light on it yesterday and Matt said the ignition timing was at about 11 degrees so within spec more or less...

I am going to give it a good service and see what difference that makes, but I can't do that until next month, so my next step is to pop the dizzy cap off and see if it's got anything wrong with it. I also have my suspicions about both the ignitor and the TPS (for an unrelated reason) so they will get checked out too.

Sounds like you need to check the mechanical timing isnt off chap

[toxo]

yo John pop in I'll check the static timing for ya

Cheers, will do. We need to get that fri88ing oil leak sorted too, it's doing my head in stinking of oil everywhere I go and Silkolene's not cheap!! I would've got you to look the other day but I thought you might have killed me if I suggested it after the CV joint

Sounds like you need to check the mechanical timing isnt off chap

Sorry, should've been clearer. When the timing light was on the car TE1 and E1 were bridged, removing any ignition adjustment from the ECU, so that 11deg was mechanical timing.

[greeny]

yo John pop in I'll check the static timing for ya

Cheers, will do. We need to get that fri88ing oil leak sorted too, it's doing my head in stinking of oil everywhere I go and Silkolene's not cheap!! I would've got you to look the other day but I thought you might have killed me if I suggested it after the CV joint

Sounds like you need to check the mechanical timing isnt off chap

Sorry, should've been clearer. When the timing light was on the car TE1 and E1 were bridged, removing any ignition adjustment from the ECU, so that 11deg was mechanical timing.

I mean the actual CAM/mechanical timing! Not the base ignition timing

[toxo]

I mean the actual CAM/mechanical timing! Not the base ignition timing

Gotcha

[toxo]

I have got a bit further with this...

There was a hole in my exhaust Fixed that.

Changed the oil + filter. Car starts better now. It was about 5000 miles old so needed doing anyway. No junk on magnetic sump plug, for whatever it's worth.

Checked the sparks and HT leads, all OK. Sparks are not too clean, not to black or wet, and are iridiums again about 5000 miles old (I know iridiums break but not this early on in life). HT leads are same age so checked resistance only, there's no corrosion and the connectors are all still solid.

Checked TPS, that's in spec.

Checked coil, that's not quite in spec but was warm and the BGB says to test from cold.

Changed rotor arm and dizzy cap. Seal on dizzy cap had gone so there had been some water and oil ingress (not sure wtf the oil came from as my dizzy -> cam seal was replaced last year!).

I have given up on things that I can do now so off to Luke's tonight! Compression test, leakdown test, check timing, mess about with ICV, etc. It's still misfiring on idle too, you can feel it through the car (solid engine mounts) and watch the rev needle. You can hear it if you kneel down by the exhaust too. I think it's just afterfiring slightly, but my exhaust isn't very free flowing so it never results in much more than a small 'phut'.

Oh yeah I pulled both ECU fuses while I did the dizzy cap & rotor arm, that way it should have forgotten about any timing retardation that it had applied with the old components...

[raptor95GTS]

loose pipe on induction side?

[toxo]

loose pipe on induction side?

Interesting We found what looked like a leaky inlet manifold gasket on cyl 2 so it's getting stripped to bits shortly - gave me an opportunity to get the turbo off and rebuilt as well.

[Quigonjay]

on this occasion, will the maifold gasket be the only thing that has changed?

[toxo]

on this occasion, will the maifold gasket be the only thing that has changed?

No, I've taken the opportunity to take the turbo off and get that rebuilt as the seals are shot. This has filled the inlet mani etc with loads of old oil which has since crustified and is blocking things up. It was oil dripping from the point where the inlet manifold meets the head that pointed to the gasket failure in the first place.

So the inlet manifold and chargecooler are getting cleaned out and the turbo's getting rebuilt, as well as the manifold, turbo and downpipe getting ceramic coated.

So sadly it won't be conclusive proof that the inlet manifold was at fault. I know you're still hunting for your fault but I think our symptoms could both be MAP failure - i.e. an air leak.

[Quigonjay]

is there a bgb test for the map sensor?

[toxo]

is there a bgb test for the map sensor?

Good question, I suspect there is but you'd need to look at the ST205 BGB on celicatech rather than the MR2 ones as they are generally all Rev2 which didn't use the MAP sensor for management.

Aside from that, I don't believe it's a MAP sensor fault, but rather that the MAP sensor and associated management expect a sealed/pressurised environment and aren't getting that. I think if your MAP sensor was bust you'd have far larger problems.

[toxo]

Here you go: http://www.celicatech.com/imagearchive/ ... /EG105.htm

[Quigonjay]

hmm, last bit looks a bit too complicated for me

[carlos9999]

ok mate.. i had a slight misfire for months, (was intermittent) then eventually 5/6 months later it was a permanent misfire. couldnt find it for love nor money. did all the usual ....plugs, leads, dizzy, rotor,coil,ecu.

turned out i had a faulty live feed on injector one. thing is i'd already checked all the wiring it was all good (had 12v's) so i ignored that for a while. anyways i come to the conclusion it was a faulty injector so i put a new one in and it still didnt fix it.. so.. back to the wiring again.. it must have been breaking down or something under load. so i took a new ignition live to it and hey presto all is good now.

so the question is.. is it a random misfire or is it isolated to one cylinder..??
if its the later, then maybe its worth investigating..