93 SE Breaking up at High RPM
Discussion
My 93 Esprit, after sitting for two weeks (don't ever do that again), started breaking up at higher (over 5k) rpm at full throttle. Symptoms and stats:
1. 93.5 SE, stock except for S4s chip and no cat exhaust.
2. Car hesitates dramatically above 5 k and misses, and bogs at full throttle at 4k or so and then backfires as if a cylinder is loading up wtih fuel, not firing and then igniting on the exhaust.
3. Car runs fine up to 3/4 throttle and 5k rpm.
4. After installing new chip, I've had an intermittent warm up issue. When first started cold, car will rev to 2k for about 2 minutes, then to 3k for 30 secnds and check engine light will come on. Revs will then drop to normal idle (1k) and check engine light goes off.
5. Car ran fine with exhaust and chip for about a month.
6. Pulled one plug and it was badly corroded. Have a new set on the way. Will try those first.
If not, what's next:
a. Coils?
b. Coil packs?
c. Ignitioin leads?
1. 93.5 SE, stock except for S4s chip and no cat exhaust.
2. Car hesitates dramatically above 5 k and misses, and bogs at full throttle at 4k or so and then backfires as if a cylinder is loading up wtih fuel, not firing and then igniting on the exhaust.
3. Car runs fine up to 3/4 throttle and 5k rpm.
4. After installing new chip, I've had an intermittent warm up issue. When first started cold, car will rev to 2k for about 2 minutes, then to 3k for 30 secnds and check engine light will come on. Revs will then drop to normal idle (1k) and check engine light goes off.
5. Car ran fine with exhaust and chip for about a month.
6. Pulled one plug and it was badly corroded. Have a new set on the way. Will try those first.
If not, what's next:
a. Coils?
b. Coil packs?
c. Ignitioin leads?
Hi,
I had same thing. Convinced myself it was wastegate related...
HT lead was busted. Was cracked/split inside the rubber boot of the plug end on the one nearest the belts (pulled too tight due to poorly routed leads, must have helped its demise). It must have been arcing away for a while, i only knew this was the point of the break when the sparkplug 'kept' the end of the lead when i pulled the boot off.
The split was well charred.
At 5k it was stumbly and hesitant at full throttle,
New leads later and she was like new
Hope yours is that easy.
Paul
I had same thing. Convinced myself it was wastegate related...
HT lead was busted. Was cracked/split inside the rubber boot of the plug end on the one nearest the belts (pulled too tight due to poorly routed leads, must have helped its demise). It must have been arcing away for a while, i only knew this was the point of the break when the sparkplug 'kept' the end of the lead when i pulled the boot off.
The split was well charred.
At 5k it was stumbly and hesitant at full throttle,
New leads later and she was like new
Hope yours is that easy.
Paul
Jeff,
Try the new plugs. If not then look at getting new plug wires. I've had to replace mine twice in 4 years.
Also check your water temp, should be above 82deg C when warm. If the thermostat isn't working correctly, the engine will cut boost and do other funny things.
Probably just plugs and wires though.
Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey/
Try the new plugs. If not then look at getting new plug wires. I've had to replace mine twice in 4 years.
Also check your water temp, should be above 82deg C when warm. If the thermostat isn't working correctly, the engine will cut boost and do other funny things.
Probably just plugs and wires though.
Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey/
JeffYoung said:
Thanks guys. Have the wires and plugs and will try to install tonight.
Question: I bought the iridium plugs from NGK -- only single prong. Thought all Esprit plus were double?
Any thoughts.
I know others are using the Iridium plugs with no problem. Just don't break the ceramic insulator.
Travis
Vulcan Grey 89SE
www.lotuscolorado.com/vulcangrey/
On full throttle?
Does the boost peg?
Does it feel like you are running out of fuel or the ignition has been cut?
If so check the waste capsule and see that the little hose has not fallen off actuator capsule.
More than likely it is plugs, I used to change mine every year because I had a similar problem. I just used the stock NGK plugs. They do erode with a light tan color burn marks.
Does the boost peg?
Does it feel like you are running out of fuel or the ignition has been cut?
If so check the waste capsule and see that the little hose has not fallen off actuator capsule.
More than likely it is plugs, I used to change mine every year because I had a similar problem. I just used the stock NGK plugs. They do erode with a light tan color burn marks.
Jeff, call me at home or cell. Bad news on my Lotus - oil return is leaking and I can't get a new one in time for the track this weekend, besides, work is killing me and I'd have no time to put it on if I had one. BMW CC does not want a Lightning on the track, so, I'm stuck since obviously the JH or the GT40 can't go either. I was thinking you could take my solt and use the TR8 or your Lotus if it gets sorted in time.
Had exactly the same problem the other week on my s4 at 3/4 throttle would rev out but at full it would miss backfire and generally sound like crap i was convinced first it was the wastegate sticking and cutting out on overboost i checked this using the pump of the seat and proved it to be fine then i thought it would be an electrical problem but my ever so helpful mechanic persuaded me to change the fuel filter and not only did the popping and farting stop the car now goes like i put another turbo on lol
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