mr2 tubby misfire
Discussion
Got a rev 3 tubby with a slight misfire and I can't pin it down which cylinder. All plugs are evenly coated. Misfire is worse when cold and boost seems to come and go. When warmed misfire is still there but not always noticeable. Got new plugs,leads,, caps and arm changed last year and only minimal milage since. Any ideas anyone?
Have you checked for error codes? If you're unsure how; locate the diagnostics port on the bottom right corner of the rear bulkhead (viewing vehicle from the rear). Connect the E1 and TE1 ports with a paperclip, turn the ignition to its 2nd position and wait for the engine management light to flash. Constant flashing means no error codes stored, if it flashes 5 times then 3 times for example that would be error code 53.
Barring that, its worth going over your ignition components again, MR2 Turbos are incredibly sensitive to underperforming ignition components, and run at their best on standard OEM parts, particularly ignition leads.
Another possibility is the coil-pack. The outer casing cracks in cold weather and lets in moisture which in turn makes the car run very lumpy especially when cold.
If you still draw a blank after those checks, maybe have a look at the timing. Easy to do yourself with a timing gun. Base timing should be set at 10deg before top dead centre.
Good luck with it.
Barring that, its worth going over your ignition components again, MR2 Turbos are incredibly sensitive to underperforming ignition components, and run at their best on standard OEM parts, particularly ignition leads.
Another possibility is the coil-pack. The outer casing cracks in cold weather and lets in moisture which in turn makes the car run very lumpy especially when cold.
If you still draw a blank after those checks, maybe have a look at the timing. Easy to do yourself with a timing gun. Base timing should be set at 10deg before top dead centre.
Good luck with it.
Basically when driving it cold it requires very gentle driving or it'll miss and hold back. Once warm its normally gone but now doing it whilst warm. Note to add. Most of my driving is just to work and back which is only 8 miles away so might go away witha longer run. I have been thinking coil to as it may be worse when wet/been raining although may just be imagining it.
I havent checked for codes yet. Ths missus says its stinks of petrol to but I cant smell it as havent got much of a sense of smell. But plugs arent black just the right colour
I havent checked for codes yet. Ths missus says its stinks of petrol to but I cant smell it as havent got much of a sense of smell. But plugs arent black just the right colour
First thing is to check for error codes!
Paper clip between te1 and e1 terminals in the diag port. May show up a code to help you out...
Don't know if this will help but its what I would of done on my old mr2 turbo.
Start from one end of ignition system and check;
Spark plugs, colouration and gapping correct. Due for replacement?
Ht leads, measure resistance, check for damage and cleanliness on plug and dizzy contact
Dizzy, plugs seat correctly, any oil leak into dizzy, worn contacts inside
Rotor arm, good condition or burnt and knackered?
King lead from dizzy to coil pack, is it in good condition and check resistance.
The coil packs fail way too often due to the position on the rear fire wall and crack for fun.
Then id pull the coil pack of fire wall with igniter. Are they sealed or cracked anywhere. Also check all contacts are making contact. I cant remember how to check for correct parameters but it will say in the bgb service manual.
May be worth checking the timing too?
Are there any other problems with the engine like loss of coolant?
Paper clip between te1 and e1 terminals in the diag port. May show up a code to help you out...
Don't know if this will help but its what I would of done on my old mr2 turbo.
Start from one end of ignition system and check;
Spark plugs, colouration and gapping correct. Due for replacement?
Ht leads, measure resistance, check for damage and cleanliness on plug and dizzy contact
Dizzy, plugs seat correctly, any oil leak into dizzy, worn contacts inside
Rotor arm, good condition or burnt and knackered?
King lead from dizzy to coil pack, is it in good condition and check resistance.
The coil packs fail way too often due to the position on the rear fire wall and crack for fun.
Then id pull the coil pack of fire wall with igniter. Are they sealed or cracked anywhere. Also check all contacts are making contact. I cant remember how to check for correct parameters but it will say in the bgb service manual.
May be worth checking the timing too?
Are there any other problems with the engine like loss of coolant?
hey mate, check the coil and ignighter under the fuse box in the engine bay, may need to take it off to check for cracks around the case, might have water inside, try spraying it with wd40 and leave to dry out, also worth checking coolent temp sensor, should throw up code 22 and messing with fuel, but ive had a dodgy one that didnt throw any codes, and just re check all ignition bits 
engine is running fine as in no smoke/no loss of coolant or oil, plugs are fresh last month, NGK coppers 1 grade cooler and I gapped them to .8
cap, arm and leads replaced either last year or end of year before but only done around 7k in that space of time anyway
exhaust tips look a little more sooty than usual and mpg not great but ive put that down to my relatively short trips to work and long cold snap.
I'll check for codes this weekend, ive never been very happy with the boost pipes fitment of the ebay intercooler i fitted(which fits s
te compared to another ebay one I had on a previous MR2). Ive got a redtec charger cooler to fit but I'll be waiting for the warmer weather of until I get my garage built before I start messing with that as I want a really good job of fitting the pipes etc.
cap, arm and leads replaced either last year or end of year before but only done around 7k in that space of time anyway
exhaust tips look a little more sooty than usual and mpg not great but ive put that down to my relatively short trips to work and long cold snap.
I'll check for codes this weekend, ive never been very happy with the boost pipes fitment of the ebay intercooler i fitted(which fits s
te compared to another ebay one I had on a previous MR2). Ive got a redtec charger cooler to fit but I'll be waiting for the warmer weather of until I get my garage built before I start messing with that as I want a really good job of fitting the pipes etc.Mine was doing this when cold, turned out to be a failed heater coil in the oxygen sensor. If yours does it constantly I'd suggest the O2 sensor itself may have fallen over.
Worth checking the throttle position sensor is setup correctly as well, that can produce some similar symptoms if it works loose (which they all will over time).
Worth checking the throttle position sensor is setup correctly as well, that can produce some similar symptoms if it works loose (which they all will over time).
Checked for codes yesterday had a 4 and a 7. Tps sensor and coolant sensor. Coolant sensor makes sense for its behaviour and will be geting replaced. Cant find a working guide for the tps sensor though just dead links. Anyone?
Also checked the base ignition timing which was a bit too advanced so retarded it back to 10 degrees which has smoothed the idle out a little. Wonder if the coolant sensor will fix my poor mpg? Or should I look at testing the o2 sensor also?
Also checked the base ignition timing which was a bit too advanced so retarded it back to 10 degrees which has smoothed the idle out a little. Wonder if the coolant sensor will fix my poor mpg? Or should I look at testing the o2 sensor also?
Checked for codes yesterday had a 4 and a 7. Tps sensor and coolant sensor. Coolant sensor makes sense for its behaviour and will be geting replaced. Cant find a working guide for the tps sensor though just dead links. Anyone?
Also checked the base ignition timing which was a bit too advanced so retarded it back to 10 degrees which has smoothed the idle out a little. Wonder if the coolant sensor will fix my poor mpg? Or should I look at testing the o2 sensor also?
Also checked the base ignition timing which was a bit too advanced so retarded it back to 10 degrees which has smoothed the idle out a little. Wonder if the coolant sensor will fix my poor mpg? Or should I look at testing the o2 sensor also?
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