MR2 - new owner... some issues
Discussion
Morning all
Picked up a rev2(i think) '92 MR2 turbo yesterday, interesting thing to drive, seems to have been heavily modified (strut braces, some sort of adjustable front shocker adjustment top mounting plates, non-standard dump valve & actuator, huge intercooler, K&N cone filter, full chav-spec exhaust, as far as i can see, probably more)
MASSIVE turbo lag, but I assume that's normal, then tries to peel your face off.
Starts and idles fine, drives fine, except...
Has a few issues:
- Tries to stall:
lifting off throttle at a junction for example, 9 times out of 10 it will bog right down and nearly stall, if i catch it it will idle fine at 800-1000.
- Misfire:
Occurs at high revs, also belches out some black smoke.
Please bare in mind that i dont know these cars AT ALL, but i know cars well.
All advice welcome!
Picked up a rev2(i think) '92 MR2 turbo yesterday, interesting thing to drive, seems to have been heavily modified (strut braces, some sort of adjustable front shocker adjustment top mounting plates, non-standard dump valve & actuator, huge intercooler, K&N cone filter, full chav-spec exhaust, as far as i can see, probably more)
MASSIVE turbo lag, but I assume that's normal, then tries to peel your face off.
Starts and idles fine, drives fine, except...
Has a few issues:
- Tries to stall:
lifting off throttle at a junction for example, 9 times out of 10 it will bog right down and nearly stall, if i catch it it will idle fine at 800-1000.
- Misfire:
Occurs at high revs, also belches out some black smoke.
Please bare in mind that i dont know these cars AT ALL, but i know cars well.
All advice welcome!
More precise details of the spec would be helpful. Many people make poor choices when modifying Mk2 MR2s.
If the dump valve (BOV) has been changed to a vent-to-atmosphere type rather than the stock recirc it can mess with the AFM on a Rev 2 (some cars are affected more than others). An aftermarket actuator where the arm isn't adjusted properly and/or an incorrect spring rate won't help. The wrong choice of aftermarket intercooler can increase lag. Is it a side mount? What brand? However lag shouldn't be massive. That suggests other possible factors at work. Is the turbo the OEM CT26b or has that been swapped out? Is it still using the stock ECU?
The black smoke means it's running rich (better that than lean!). The misfire could be because the plugs are fouling. What make and heat range are they? Other possible causes are dizzy cap/rotor wear (turbos tend to eat them) and c**p aftermarket replacement HT leads. Use OEM or NGKs.
If the dump valve (BOV) has been changed to a vent-to-atmosphere type rather than the stock recirc it can mess with the AFM on a Rev 2 (some cars are affected more than others). An aftermarket actuator where the arm isn't adjusted properly and/or an incorrect spring rate won't help. The wrong choice of aftermarket intercooler can increase lag. Is it a side mount? What brand? However lag shouldn't be massive. That suggests other possible factors at work. Is the turbo the OEM CT26b or has that been swapped out? Is it still using the stock ECU?
The black smoke means it's running rich (better that than lean!). The misfire could be because the plugs are fouling. What make and heat range are they? Other possible causes are dizzy cap/rotor wear (turbos tend to eat them) and c**p aftermarket replacement HT leads. Use OEM or NGKs.
Edited by Red Devil on Sunday 6th July 10:54
Thanks for that, I'v taken some photos now, yes its a side-mount intercooler, hopefully the photos will help...
The dump valve does vent to air, looks like the return for that has been (badly) plugged.
Is there any reason someone would have cut the tube from the actuator to the turbo?? (see photo)
Its a bit of a chav-stylee mess, needs the red stripe removing and the wheels painting...
The dump valve does vent to air, looks like the return for that has been (badly) plugged.
Is there any reason someone would have cut the tube from the actuator to the turbo?? (see photo)
Its a bit of a chav-stylee mess, needs the red stripe removing and the wheels painting...
It looks to have a Blitz BOV, filter, Tein coilovers, HKS FCD, forge actuator and not sure on the side mount intercooler probably an ebay or toyosport job. Also the strut brace is a standard item.
The vacuum line from the turbo which has a bolt in it needs to be connected to the open vacuum from the actuator to the right. At the moment its keeping the wastegate closed giving unlimited boost. Does the car have a boost gauge? It should be reading 0.8-1.0 max.
I would also remove the FCD until you can check and have some means of adjusting the fuelling, as at the moment it is altering the signal from the MAF to the ECU. Which results in the engine operation not being true to what is actually entering the engine.
The vacuum line from the turbo which has a bolt in it needs to be connected to the open vacuum from the actuator to the right. At the moment its keeping the wastegate closed giving unlimited boost. Does the car have a boost gauge? It should be reading 0.8-1.0 max.
I would also remove the FCD until you can check and have some means of adjusting the fuelling, as at the moment it is altering the signal from the MAF to the ECU. Which results in the engine operation not being true to what is actually entering the engine.
I don't know why people buy cars especially an MR2 turbo without doing their homework...Very strange to me.
Well for sure you need to remove the Bov asap and disabled the FCD until you have done a full inspection of the car's health and got a boost gauge.
The FCD removes the ecu's safety fuel cut of 10psi. Can be dangerous if you don't know the car's health or what you are boosting to. Also rev 1/2 turbos do not have metal head gaskets and don't like much more than 14psi /1 bar
OEM bov can be got quite easily, it will make your car run a whole lot better. I recommend join IMOC.
On a plus note your wheels look fine. Pls don't paint them all black -.-
Well for sure you need to remove the Bov asap and disabled the FCD until you have done a full inspection of the car's health and got a boost gauge.
The FCD removes the ecu's safety fuel cut of 10psi. Can be dangerous if you don't know the car's health or what you are boosting to. Also rev 1/2 turbos do not have metal head gaskets and don't like much more than 14psi /1 bar
OEM bov can be got quite easily, it will make your car run a whole lot better. I recommend join IMOC.
On a plus note your wheels look fine. Pls don't paint them all black -.-
I don't know why people buy cars especially an MR2 turbo without doing their homework...Very strange to me.
Well for sure you need to remove the Bov asap and disabled the FCD until you have done a full inspection of the car's health and got a boost gauge.
The FCD removes the ecu's safety fuel cut of 10psi. Can be dangerous if you don't know the car's health or what you are boosting to. Also rev 1/2 turbos do not have metal head gaskets and don't like much more than 14psi /1 bar
OEM bov can be got quite easily, it will make your car run a whole lot better. I recommend join IMOC.
On a plus note your wheels look fine. Pls don't paint them all black -.-
Well for sure you need to remove the Bov asap and disabled the FCD until you have done a full inspection of the car's health and got a boost gauge.
The FCD removes the ecu's safety fuel cut of 10psi. Can be dangerous if you don't know the car's health or what you are boosting to. Also rev 1/2 turbos do not have metal head gaskets and don't like much more than 14psi /1 bar
OEM bov can be got quite easily, it will make your car run a whole lot better. I recommend join IMOC.
On a plus note your wheels look fine. Pls don't paint them all black -.-
Best bet maybe to drop it off to a specialist for a "bill of health", maybe return to stock.
There's certainly a lot you can do yourself (including polishing the wheels!) but they're complex cars, relatively difficult to work on, and you've got a car with unknown mods. You're really in at the deep end.
The misfire is probably an issue on the ignition side -- dizzy, rotor, leads, etc. The black smoke unburnt fuel. The idle issue may be a dirty IAC. Good recent post with a link on MR2OC.
The lag is a big puzzle. Unless -- and I can't see any evidence of it from the pics -- someone has fitted a whopping great big turbo.
Links to the Big Green Book -- Toyota Workshop Manual -- in the "know your 2" tab on MR2OC.
There's certainly a lot you can do yourself (including polishing the wheels!) but they're complex cars, relatively difficult to work on, and you've got a car with unknown mods. You're really in at the deep end.
The misfire is probably an issue on the ignition side -- dizzy, rotor, leads, etc. The black smoke unburnt fuel. The idle issue may be a dirty IAC. Good recent post with a link on MR2OC.
The lag is a big puzzle. Unless -- and I can't see any evidence of it from the pics -- someone has fitted a whopping great big turbo.
Links to the Big Green Book -- Toyota Workshop Manual -- in the "know your 2" tab on MR2OC.
Thanks guys!
Don't worry, I didnt buy it as such, I've sort of "ended up" with it (all legal and above board obviously!)
So not looking to spend big money at all, at this point its a toy.
The turbo looks to be the standard unit, I had a good poke about yesterday afternoon, and found a couple of dodgy vacuum pipes, reconnected the one from the turbo to the actuator, plugged the other one "VTV".
2 of the HT leads weren't fully seated into the block, I'm sure that cant help!
I've joined the MR2OC forum, seem to be a helpful bunch too :-)
anyhoo, MOT this morning so i'll have a chance to have a good blast about beforehand...
Don't worry, I didnt buy it as such, I've sort of "ended up" with it (all legal and above board obviously!)
So not looking to spend big money at all, at this point its a toy.
The turbo looks to be the standard unit, I had a good poke about yesterday afternoon, and found a couple of dodgy vacuum pipes, reconnected the one from the turbo to the actuator, plugged the other one "VTV".
2 of the HT leads weren't fully seated into the block, I'm sure that cant help!
I've joined the MR2OC forum, seem to be a helpful bunch too :-)
anyhoo, MOT this morning so i'll have a chance to have a good blast about beforehand...
I would try and pin down some of the basics, give it a proper service and ensure you are getting a decent spark to all cylinders (turbo's are notorious for eating the dizzy caps), I would get a leak down test on the turbo to ensure of its condition, I would compression test each cyclinder to ensure no issues there.
Also, as above, disconnect the FCD, this will then let the Toyota ECU limit fuel at I think 15psi on the rev 1/2, was lsightly higher for the rev 3+ which will ensure you are not over boosting.
I would get a decent boost gauge on the car so that you know what it is doing under full throttle.
Car looks good for its age and has some decent aftermarket parts on it, just start ticking off the basics so that you know you have a solid mechanical base underneath you.
Also, as above, disconnect the FCD, this will then let the Toyota ECU limit fuel at I think 15psi on the rev 1/2, was lsightly higher for the rev 3+ which will ensure you are not over boosting.
I would get a decent boost gauge on the car so that you know what it is doing under full throttle.
Car looks good for its age and has some decent aftermarket parts on it, just start ticking off the basics so that you know you have a solid mechanical base underneath you.
Timing could also be off when it comes to misfiring get it properly adjusted with a timing light set of spark plug leads wouldnt do any harm and reset the ecu see if you notice any difference with lag. Usually around 90k your worth getting a steal head gasket on as the old fibre one disintegrate by that time.
TheRealFingers99 said:
The lag certainly isn't normal on Rev1/2 turbos.
the whole reason for a twin scroll turbo design is to reduce lag. There is still a small amount, but it's not intrusive like earlier turbocharged engines were.Perhaps the OP is talking about boost threshold, though that wasn't particularly high on my MR2.
Sadly the OP's car is a textbook example of the kind of MR2 you should avoid. It's had at least one, and likely several incompetent owners that have tried to 'improve' it.
Edited by Mr2Mike on Sunday 13th July 16:29
Mr2Mike said:
the whole reason for a twin scroll turbo design is to reduce lag. There is still a small amount, but it's not intrusive like earlier turbocharged engines were.Perhaps the OP is talking about boost threshold, though that wasn't particularly high on my MR2.
Yes I may be confusing lag with the onset of boost (not being a turbi-ist)
I notice boost coming in at about 3000 rpm + and only under heavy throttle. The boost gauge shows negative almost all of the time other than when i basically floor it, I then get up to about 12psi.
That's pretty normal. As soon as the gauge (but the OE gauges are pretty useless) reads + you have boost.
On the Rev 1s it's pretty much all over by 5.5k (but just about everything will be well behind you). On the Rev3s boost comes in slightly later and runs all the way to the red line (straight swap in so far as anything so damn awkward to get to is a straight swap).
The Terry Heick (HP Books) "Toyota MR2 Performance" book is probably the best "all in one place" source of info (albeit already a bit outdated in terms of ECUs, etc.)
There's likely to be someone nearby on MR2OC or IMOC who can take a peek, give you a good idea of what's right and wrong.
As long as you don't get FWD (or BMW) clumsy with throttle inputs (especially lift off) just about everything is recoverable.
On the Rev 1s it's pretty much all over by 5.5k (but just about everything will be well behind you). On the Rev3s boost comes in slightly later and runs all the way to the red line (straight swap in so far as anything so damn awkward to get to is a straight swap).
The Terry Heick (HP Books) "Toyota MR2 Performance" book is probably the best "all in one place" source of info (albeit already a bit outdated in terms of ECUs, etc.)
There's likely to be someone nearby on MR2OC or IMOC who can take a peek, give you a good idea of what's right and wrong.
As long as you don't get FWD (or BMW) clumsy with throttle inputs (especially lift off) just about everything is recoverable.
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