Engine hesitation

[Chris T]

Ok guys I'm sure I posted this problem on her some time ago but can't find it again.

This problem started as a very occassional hesitation - and seems to happen at any rev range. Now its doing it daily - and is really doing my head in as I was trying to sell the car.

The hesitations can be anything from a split second up to about 5 second - and its really no joke when your overtaking and it happens. On occasions - at low reves / low speed the engine has even stalled.

Could anyone help me with this as I'm tearing my hair out! Somebody mentioned a re-map of my standard ecu may help? Would changing the sparks and coil packs have any effect? Ive run a bottle of injector cleaner through with a full tank of super but no change! Also, could my BOV be causing this?

Trying to sell it so want to spend as little as poss! Got more points this year and my insurance company want £1100 premium so its got to go.

Help!

[Moff]

When were the plugs last changed, and what plugs are in there ?

I now someone who has this prob, turned out they had 1.1mm gapped instead of 0.8mm

[Nero]

Id look at the air flow meter (afm) mine did almost the same thing although mine never stalled

it turned out to be the solder on the connections inside had cracked I re soldered the joints and it was as good as new

[Chris T]

Originally Posted by Moff

When were the plugs last changed, and what plugs are in there ?

I now someone who has this prob, turned out they had 1.1mm gapped instead of 0.8mm

Ive had the car a year and never changed them. Have no idea what plugs are in there. The problem has worsened over the past few months rather than being a constant problem - when I first got the car it was fine.

[Chris T]

Originally Posted by Nero

Id look at the air flow meter (afm) mine did almost the same thing although mine never stalled

it turned out to be the solder on the connections inside had cracked I re soldered the joints and it was as good as new

Thanks, thats something to check

[ISJ]

I've had a slowly developing problem for a few months now. Last night I've taken my splitfires out and reverted back to standard coils. So far so good, but as the problem was intermittent then it is too early to say if it is a definitive fix.

This problem is very common, mainly due to modifications causing the standard ECU to retard the ignition and run rich mixtures.

Whats your fuel economy like? **** I bet.

It can be a number of things, plugs, coils, AFM, ICV, Injectors, poor fuel, ECU, Boost leak, Vacuum leak, BOV leak, you name it!

[Moff]

Originally Posted by Chris T

Ive had the car a year and never changed them. Have no idea what plugs are in there. The problem has worsened over the past few months rather than being a constant problem - when I first got the car it was fine.

Start with a new set of plugs

Then buy one of these, gave me 60 miles extra a tank out of my Stagea and should be changed every 60k, but never do..

Just Lambda, Skyline lambda sensors, Bosch and NTK zirconia and titania sensors by post

[Nero]

I bought one of them Moff, I was also very impressed with the probe and the company.

[Chris T]

Originally Posted by ISJ

I've had a slowly developing problem for a few months now. Last night I've taken my splitfires out and reverted back to standard coils. So far so good, but as the problem was intermittent then it is too early to say if it is a definitive fix.

This problem is very common, mainly due to modifications causing the standard ECU to retard the ignition and run rich mixtures.

Whats your fuel economy like? **** I bet.

It can be a number of things, plugs, coils, AFM, ICV, Injectors, poor fuel, ECU, Boost leak, Vacuum leak, BOV leak, you name it!

Fuel economy is crap. 18 max, usually 12-15MPG. I'm going to change the plugs as a first port of call, and get the ecu remapped.

[Chris T]

Originally Posted by Moff

Start with a new set of plugs

Then buy one of these, gave me 60 miles extra a tank out of my Stagea and should be changed every 60k, but never do..

Just Lambda, Skyline lambda sensors, Bosch and NTK zirconia and titania sensors by post

Right, Im going to book it it for a set of new plugs. recomedations for plug type and gap? Already changed the Lambda and it made absolutuly no difference to the running or fuel economy.

[ISJ]

Originally Posted by Chris T

Right, Im going to book it it for a set of new plugs. recommendations for plug type and gap? Already changed the Lambda and it made absolutely no difference to the running or fuel economy.

Simply fitting new plugs may not cure anything. You can "mask" the problem by putting colder plugs in but it wont cure it. (If you wanna do this put some Grade 8 plugs in - Something like NGK BKR8 or BCPR8 they're both the same - but ferr christ sakes double check this with your tuner!) In all likelyhood, putting those plugs in will make the car drive well again, but doesn't cure the problem, it'll still be happening in your engine, you just wont get the misfire happening!

You shouldn't really re-gap iridium plugs such as those and they are most commonly available in 1.1mm gap form, you shouldn't have any problems re-gapping them if you are very careful - but it isn't advised - apparently.

I'll guess you have full exhaust system and induction mods - right?

Those mods alone will cause your already rich running stock ECU to put more fuel in and retard the ignition even more - it's a safety system to prevent damage from detonation (and Internet mechanics - stole that bit from SAU).

Really you need to either fool the ECU with a signal conditioner such as an SAFC, re-map your ECU or get a new ECU such as PowerFC etc.

Now, this is where I'm at with mine, you may wish to take this as a general info as it may not be strictly applicable to you and your car, but appears to be for mine and many others. I can only say get the garage you take it to, to look at everything and try a few things first. Maybe change the coils, whip the plugs out and check their condition/gap/cold rating (low=hot high= cold).
Standard plugs for these are something like 5's but most people generally have to use 8's to get them to run right with breathing mods.

Oh I'll point out now that I'm not a mechanic - but I have had my car for a number of years and have experiencd all this sh*t before and these are mine and others in my positions' opinions. Like I said earlier, just last night I had the top of my engine in bits and fitted my old coils, which does seem to have made a difference - so far. I also have grade 7 plugs in at the mo, which have been fine for over 18 months, but now it misses on 7's. I have 8's to go in, but I wanted to rule out coils first - hence swopping them last night. (I've already gone down the lambda sensor route.)

[ISJ]

And re-reading your OP, I'm beginning to think coils:

a) it's a problem that started intermittantly and small.

b) got worse over time and more pronounced.

[Andy W]

could also be something like a split intercooler pipe or a fuel pump packing up

[Moff]

Get a Lamabda too... !!!!!!!!!!!!!!!!!!!!!!!

[Chris T]

Originally Posted by ISJ

Simply fitting new plugs may not cure anything. You can "mask" the problem by putting colder plugs in but it wont cure it. (If you wanna do this put some Grade 8 plugs in - Something like NGK BKR8 or BCPR8 they're both the same - but ferr christ sakes double check this with your tuner!) In all likelyhood, putting those plugs in will make the car drive well again, but doesn't cure the problem, it'll still be happening in your engine, you just wont get the misfire happening!

You shouldn't really re-gap iridium plugs such as those and they are most commonly available in 1.1mm gap form, you shouldn't have any problems re-gapping them if you are very careful - but it isn't advised - apparently.

I'll guess you have full exhaust system and induction mods - right?

Those mods alone will cause your already rich running stock ECU to put more fuel in and retard the ignition even more - it's a safety system to prevent damage from detonation (and Internet mechanics - stole that bit from SAU).

Really you need to either fool the ECU with a signal conditioner such as an SAFC, re-map your ECU or get a new ECU such as PowerFC etc.

Now, this is where I'm at with mine, you may wish to take this as a general info as it may not be strictly applicable to you and your car, but appears to be for mine and many others. I can only say get the garage you take it to, to look at everything and try a few things first. Maybe change the coils, whip the plugs out and check their condition/gap/cold rating (low=hot high= cold).
Standard plugs for these are something like 5's but most people generally have to use 8's to get them to run right with breathing mods.

Oh I'll point out now that I'm not a mechanic - but I have had my car for a number of years and have experiencd all this sh*t before and these are mine and others in my positions' opinions. Like I said earlier, just last night I had the top of my engine in bits and fitted my old coils, which does seem to have made a difference - so far. I also have grade 7 plugs in at the mo, which have been fine for over 18 months, but now it misses on 7's. I have 8's to go in, but I wanted to rule out coils first - hence swopping them last night. (I've already gone down the lambda sensor route.)

Thanks for the help! Yeah im running an apexi super intake, & 4" full s/s exhaust system & decat pipe, Greddy intercooler, BOV. I'll get back to this with the results in a couple of weeks when take it down to Triton in Bournemouth.