Author Topic: poor idle and part throttle hesitant on a turbo conversion  (Read 4140 times)

Offline timmitime

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poor idle and part throttle hesitant on a turbo conversion
« on: January 11, 2012, 08:23:55 pm »
Just a quick note to see if anyone has a opinion on this problem, I have a 1.6 8v polo engine in a lupo, Which i have  turbo'd, I am running full g40 management, k03, Lowered compression, newman turbo g40 cam, etc etc, The fault i'm having is the car starts and runs fine, But when you try to drive it normally it hesitates and misfires, but if you give it a bit more throttle it clears and pulls fine, Also when you pull up to a stop is hunts and dies, But starts fine straight away. I am in the process of trying to find a aea 1.6 8v vernier pulley to get the cam timing perfect as i think this may be causing something. But I just wondered if this has happened to anyone else ? I only need it to be running ok so i can get it mapped properly as i'm running a psd k03 map to do some steady miles in it . Any help would be good thanks

Offline Andy

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #1 on: January 11, 2012, 09:31:34 pm »
Worth checking your base ignition timing as a starter. What injectors are you running with that chip at the moment?

Offline timmitime

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #2 on: January 11, 2012, 09:36:54 pm »
Im running g60 injectors and i'm going to check timing tomorrow, Are you the Andy of ppp ?

Offline N1CKY

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #3 on: January 12, 2012, 01:50:08 am »
Not sure if it will make that much of an issue but do you have the lambda wired up ? And yes he is.

Offline PeteG40

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #4 on: January 12, 2012, 07:17:53 am »
do you know what injectors and map sensor the chip is for?

Offline Andy

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #5 on: January 12, 2012, 09:38:48 am »
To be fair, even if it's for 250cc injectors and stock MAP sensor it's still a map for a 1272cc 8:1 compression motor, not for something with 20% more capacity and a higher compression ratio.

Having said that, it's worth checking the basics like cam timing and ignition timing, and then having a run through the sensors (including closed & open-throttle switches) to check they're working properly.

Are the misfires you're getting very sharp-sounding, cracks/pops? If so, that'd suggest it's a lean misfire. Overly rich usually means it bogs down and misfires can sound quite 'wet'.
« Last Edit: January 12, 2012, 09:41:06 am by Andy »

Offline PeteG40

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #6 on: January 12, 2012, 09:54:18 am »
he does say its lowered compression.  Either way, the map won't be the best for your set up and it sounds like yoru car needs setting up and mapping properly!

Offline Andy

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #7 on: January 12, 2012, 12:44:02 pm »
Yeah, I had in my head that it was 8.8:1 CR though - but can't find an email where Steve said that, so it might've been someone else.

Do you know what motor/setup the PSD chip you bought was for?

Offline youngprodigys

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #8 on: January 12, 2012, 06:34:44 pm »
could be a faulty injector also.

Offline timmitime

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #9 on: January 12, 2012, 07:01:19 pm »
Yeah it's bogging down and clearing when it is given a bit more throttle, I'm getting a vernier sorted as soon as i can get it posted and going to check all sensors probably sat, Have you got and  resistance readings for throttle switches and co pot and water temp sensors etc ? I am also doing the 6psi mod on sat aswell. The car is booked in with ppp on feb 19th to be mapped but I wanted to get it right so we don't spend half the time sorting this fault out. The compression ratio is from memory 7.9:1 I think the psd chip says 250cc k03 I just thought it would be better than the stage 5 250cc injector supercharged chip that i was running it on. I'm going to pull the plugs out sat also and have a look at the colour they are heat range 7 hks iridiam jobs which I had in stock from my skyline

Offline hayesey

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #10 on: January 13, 2012, 09:18:40 am »
to be honest, like Andy said, it's probably going to run like a sack of shit with any chip made for a 1272cc engine in it.  Even a difference in C/R can make a big difference. 

When I built mine I had a chip designed for basically exactly the same engine but a higher C/R than mine was just to get me to Andy's for remapping and was lean as hell, ran horribly.  Just need to be confident the other parts of the engine are ok.

Offline youngprodigys

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #11 on: January 16, 2012, 08:23:24 pm »
ive read this again now, this is the pressure switch thing, mine wasnt working right when i first installed it and it ran like above - hesitates and a misfire until you get a bit of load on it, my switch was sticking- once i diagnosed it i cleaned it out and got some wd on it...sorted! so if he hasnt got one yet - a big point in that direction, might aswell rule it out seeing as he needs one anyway

Offline timmitime

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #12 on: January 17, 2012, 05:45:56 pm »
Yeah I've got the boost switch now I'll fit it in the next few days are you the guy I spoke to at e38 ? about the k03 conversion ?

Offline timmitime

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #13 on: February 13, 2012, 04:06:23 pm »
Checked everything I can now on this and it seems to be a mapping issue because I changed the oil today ready for it's mapping session Sunday was nearly all fuel ! And it was shell optimax fuel at that ;D ! Took the plugs out and they were black so cleaned them up and refitted them. Fitted up my oil cooler and carried out the 6psi mod and it now drives better but still hesitant off throttle and bogs down and idles poor, But still starts fine when it does cut out. So I've done 20 steady miles in it and it drives loads better. But its going to have to go down to PPP Sunday being towed by my mk2 golf vr6 golf but never mind, Just means more fun bringing it home and if it does die i can drag it back  ;). Wish me luck I'll post something Sunday to let everyone know how it went  ;D ;D

Offline Yoof

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Re: poor idle and part throttle hesitant on a turbo conversion
« Reply #14 on: February 13, 2012, 06:34:57 pm »
It's never good getting towed to a mapping session!

You need a shit load of fuel to be contaminating oil, especially if you've got the oil hot (fuel will usually evaporate).

I'd check as much of the mechanical side prior to mapping, you can't map out a mechanical fault.