CA18DET hesistation/bogging/backfiring on full throttle HELP!

[jay1017]

Hi guys, this is my first post on here!

I'm having a massive issue with my 13, which is when accelerating at WOT, the car will bog down hesistate & backfire at around 4-5k rpm, it won't go above that at WOT, however its fine at partial throttle.

I can't find any solutions on the internet and have tried everything I can think of, so far I have

- Gapped spark plugs
- Installed walbro 255 (thought the old pump was dying, turns out it wasn't)
- Looked for any loose couplers on intercooler piping
- New wastegate (old one was leaking)

The car boosts to approx 12psi (spike) on the standard wastegate, current mods on the car are as follows

Fmic
3" t-back exhaust
Cone filter with maf adapter
Boost gauge
Boost controller (stock boost)
Stage 1 chip (not installed, not sure if putting that in will help)
Bigger alloy radiator
Walbro 255


Praying that somebody on here has a solution, thanks in advance!

[skyshack]

Compression test.

Warm, dry and wet with a few cc of oil down each bore, wide open throttle.

[Dastardly]

And possibly rusty fuel tank.

[dukey]

Boost cut/ fuel cut.

Stage 1 should sort that

[jay1017]

Compression test.

Warm, dry and wet with a few cc of oil down each bore, wide open throttle.

I'm 90% sure compression is good, will give this a try though.

Thanks

And possibly rusty fuel tank.

Fuel tank seems fine looking at it from the bottom, when I did the pump there was rust at the top not too bad on the outside though. No rust inside the tank, all seems clean.

Boost cut/ fuel cut.

Stage 1 should sort that

It backfires though, which made me believe it isn't the fuel cut that you hit when you are on the stock chip.

I have a stage 1 hdev lying around though, will try to have that soldered in the ecu when I get the chance, thanks!

[dukey]

Mine used to make one hell of a noise

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[Dastardly]

Check the wiring to the fuel pump, make sure it's getting the full 12v. Does the fuel filter need changing? Are the injectors working properly? Have you seen for yourself the compression results?

[jay1017]

Check the wiring to the fuel pump, make sure it's getting the full 12v. Does the fuel filter need changing? Are the injectors working properly? Have you seen for yourself the compression results?

I did the fuel pump & wiring 3 days ago, so all good.

Fuel filter is new

Injectors are working (im guessing)

Haven't seen compression myself but will do end of next week

[pointz]

Boost cut/ fuel cut.

Stage 1 should sort that

I say fuel cut is also possible as freeflow exhaust and filter will improve spool time and gain so could just be spiking and hitting fuelcut.

Otherwise as stated already comp test and do a pressure test on intercooler pipework (visual inspection wont show a leak unless its obvious)

Leaning more towards boost/vac leak tho!

[jay1017]

I say fuel cut is also possible as freeflow exhaust and filter will improve spool time and gain so could just be spiking and hitting fuelcut.

Otherwise as stated already comp test and do a pressure test on intercooler pipework (visual inspection wont show a leak unless its obvious)

Leaning more towards boost/vac leak tho!

Will do both. I had this issue on standard ic setup as well, so doubt it is vac/boost leak, but will give it a go.

Cheers

[pointz]

Yea and 20+ year old oem intercoolers leak like sieves 😁

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[skyshack]

I suspect oil fouling. They come out clean with white/tan electrodes and black carbon on the end of the body.

What grade are the plugs?

What is the turbo condition? Are you running a one way valve in the breather to stop it smoking?

If you have 7's fit 6's. BCPR6EIX-11 are now available and are the correct pre-gapped plug to replace the expensive PFR6A-11. Fine tip electrode plugs can tolerate a wider range of conditions than copper plugs.
http://www.sparkplugs.co.uk/ngk-irid...ug-bcpr6eix-11

[jay1017]

I suspect oil fouling. They come out clean with white/tan electrodes and black carbon on the end of the body.

What grade are the plugs?

What is the turbo condition? Are you running a one way valve in the breather to stop it smoking?

If you have 7's fit 6's. BCPR6EIX-11 are now available and are the correct pre-gapped plug to replace the expensive PFR6A-11. Fine tip electrode plugs can tolerate a wider range of conditions than copper plugs.
http://www.sparkplugs.co.uk/ngk-irid...ug-bcpr6eix-11

Whats oil fouling?

Stock plugs and turbo virtually has no play, breather system is stock

[ANDY black s13]

When I have have had the same issue it was a boost leak from a badly made pipe (bead roll was crooked) and silicone joiner was 'pinched; by the 'T' bolt clamp
it could hold so much pressure but WOT it didn't like at all,boost leak test it took over 15 psi too show the leak
couldn't find it on the car so I had to coble the cooler and pipework with tire pump into my bath (full of water) to find it

[skyshack]

Whats oil fouling?

Wrong grade of plug runs outside self cleaning temperature range.
http://www.ngkntk.co.uk/index.php/te...fouling-range/

At other end of temp range it could be pre-ignition. If the det sensor is working it pulls the timing and goes very rich.

[jay1017]

Thanks for all the help peeps, will try out what I can this weekend and hopefully have the car dialled in

[suixo]

Check the CAS, I had the same symptoms yesterday and it turns out my CAS went bad. Hard to turn (the shaft) and encountering resistance on certain points of the turn. The timing was way off and I couldn't get it anywhere near 15º.

[jay1017]

Turns out I had a boost leak, however now I'm overboosting even with the wastegate hooked up to the throttle body boost source, will have a stage 1 chip in and see how things go and keep this updated.

Also, my FPR wasn't hooked up to a boost source, which I have also now fixed.

Cheers

[pointz]

Turns out I had a boost leak, however now I'm overboosting even with the wastegate hooked up to the throttle body boost source, will have a stage 1 chip in and see how things go and keep this updated.

Also, my FPR wasn't hooked up to a boost source, which I have also now fixed.

Cheers

Fpr shouldn't be connected to boost source mate it should be connected up at back of inlet plenum and go directly to fpr.

Check the vac line to actuator as if this has even a pin hole or slight split it will basically act as a bleed valve and not allow pressure to reach actuator.

Also do you have it hooked at nipple under tb or the one on side of plenum?

[jay1017]

Fpr shouldn't be connected to boost source mate it should be connected up at back of inlet plenum and go directly to fpr.

Check the vac line to actuator as if this has even a pin hole or slight split it will basically act as a bleed valve and not allow pressure to reach actuator.

Also do you have it hooked at nipple under tb or the one on side of plenum?

Fpr is hooked up to the one you stated, I forgot to mention that

For some reason, I overboost when I run the nipple on the turbo to the wastegate, so I ran the boost souce from the front/side of plenium where I plumbed my boost gauge which doesn't really seem to help much either although itll keep boost a little more stable at around 12psi, weird.

I've swapped out the wastegate as well, because I thought the old one was bad.. Ill try to put the old wastegate back on and see what happens