[Mk2] [Turbo] Car bogging down/sluggish on boost, please help

[David21]

I'm not too sure what to problem is with my car. I have searched to forum high and low but cannot seem to find the exact same problem as what i'm having

Right here goes, i'll start with my current mods so you have a bit of any idea what i'm running;

Rev 3 Turbo - Apexi Air intake, Apexi Boost controller, ct20b, berk downpipe and japspeed exaust, Greddy I/C.

I have a problem where by once the car is fully warmed up ready to boost. If i plant my foot to the floor in third or fourth gear the car doesn't seem to accerlerate as normal, just seems sluggish and not as responsive as it used to be. coming up to about 5k revs or so it will usually take off as normal however sumtimes it almost feels as though it's bogging down right from 4k to 5.5k or so.

If i lift off slightly from full throttle when it is slugish around 4 -5.5k revs the car will take off as normal and feel as though it is running freely and running smooth.

Sometimes when it is bogging down i almost feel to scared to keep my foot planted as it feels like something is going to go bang!

it's almost as though the car is overfuelling?

I have checked for fault codes and there are none. I have reset the ECU removing all of the required fuses, this has not seemed to have fixed it. I have also changed the dizzy cap and rotor arm.

The plugs were changed around 8k and they are the ngk irridium grade 7 colder plugs. I had the issue before i fitted my Greddy I/C and nothing has improved with regards to the issue after fitting it. I have also checked for boost leaks with the soapy water method and there are none.

If anyone could shed some light on this or has any ideas then i would be much appreciated. If you have any questions as to other things i may have checked and forgotten to mention then let me know.

The car is also of course always ran on shell v power.....

[summ0004]

Many possiblities.

1. Could try looking at other ignition components like cap/rotor arm/leads if they havent been replaced in last 12-18 months.

2. Also check the ignition timing making sure its 10 degrees, theres a post on knowledge base how to do this.

3. Check for ecu error codes and/try resetting the ecu

4. Faulty sensors or throttle cable loose/sticky

[djpkins]

def sounds like an ignition prob...

[RobCrezz]

I had a similar problem and replacing the ecu coolant temp sensor sorted that (bogging etc).

[David21]

Many possiblities.

1. Could try looking at other ignition components like cap/rotor arm/leads if they havent been replaced in last 12-18 months.

2. Also check the ignition timing making sure its 10 degrees, theres a post on knowledge base how to do this.

3. Check for ecu error codes and/try resetting the ecu

4. Faulty sensors or throttle cable loose/sticky

I have changed the cap and rotor arm recently. I havn't changed the leads though however leads should last a good 60,000 miles surely? I could always try the ones on my Dad's tubby it's just a pita to change them lol.

Ignition timing is something i thought of too, which i will try and check. I have noticed also the car slightly spluttering on ticket over.

There are no fault codes except the code for the secondry throttle sensor, which i don't have as i don't have TRC - i've heard some people get this though and it's something to ignore.

I have reset the ecu also which hasn't really cured the problem.

Rob - i've seen the ECU temp sensor can cause issues as you have metioned, think it was funily enough in one of you old posts. How much are they? IRC £35 or so?

Thanks for the feedback guys, keep the ideas coming . I'm tempted to go to Rogue as i've heard good things about them fault finding, however i don't want to end up with a huge bill for labour just fault finding lol. Plus it's about 77 miles from me also.

[summ0004]

When you mentioned the spluttering tick over some other possibility popped into my head.

I had a similiar problem on mine a while back and eventually found one of the small vacuum hoses near the throttle body to have a split in it. Was causing my tickover to be erratic when stationary and my fuel consumption went up from around 30 mpg on motorway runs to less than 25 mpg.

[David21]

Yea i see what you mean. I am going to see Luke tomorrow at Pacific Works and see if he can pin point it. I think it needs a second expert opinion on this. It's not the easiest of things to explain, i think you almost have to drive the car to get the idea.

Hopefully Luke will be able to diagnose it tomorrow

I don't care if it's something simple, of course i would rather it be as it will be cheaper to fix then

[bobhatton]

Have a look at the coil, thay slit and let water in.

Bob

[David21]

Right i have an update - sort of lol

Went to see Luke at Pacific Works yesterday. He had a go in the car himself and he said it seems okay , which strangely enough when i was in the passenger seat it felt fine! .

After going back to the workshop the only thing he could spot just by looking over and checking hoses etc was the king lead was very close to a metal braided hose.

He said when coming on boost there it alot of power coming thorugh the king lead and if it is touching or near metal it can sometime cause interferance/delay or loss of power.

He cable tied it out of the way and suggested i give it a go and see how it feels as he thought the car seemed fine - so did i by now!

So on the way home i drove back with the boost controller off just to test and it seems to be pulling fine now, no hesitation and pulling as it should be. I hope it is not an intermitent problem as it maybe quite hard to find!

So, so far so good, if it keeps running as it should from now the conclusion was either the king lead was tounching/close to metal or a good motorway run just sorted it out!

Although it seems something straight forward i still don't mind taking the 120 mile round trip to get it checked out as it means i get to go for a nice drive anyway

If it starts happening again i'll post back up, but as for now (fingers crossed) it's fixed Thanks for the feedback everyone. I always feel it's only nice to report back with the fix as there are so many un-solved threads on the forum that are frustrating when your using it to fault find your problem lol

[MRGEN3TURBO]

Brought this up from the dead but after searcing through the site this is a similar to the problem I'm having now... Just installed a blitz K1 turbo on my rev 3 turbo, feels like its retarding timing under boost, nowhere near as much power as it should have. Checked for error codes - none, checked for boost leaks - all ok.

I have a power fc ready to go in, just needs tuning, does anyone think its worth connecting to check the sensors - is this worth doing?