1jz boost problem

[triptek]

Need some help guys diagnosing a problem with my 1jz cressy. Just got the conversion finished and decided to take it for a test drive. All was good until it started to come on boost, the motor will not rev past 3.5-4k rpm and just backfires/hesitates. Things that i'v changed and checked so far:

Coils
Ignitor
ECU
Map sencer
Spark plugs (2 different types)
Fuel filter
Walbro fuel pump
Checked all ic pipes for leaks

This did nothing to help it. What do ya think i should try next. It's a jzx90 motor aswell.

[Cuzzo]

check tps?

[Endless]

What are the coilpack connectors like, still got the insulation which separates the pins inside them?

[Xistant]

i'd say map, rough/ low idle?

[yotamotion]

I know it might sound stupiod but.. as well as checking ic pipes for leaks check all clamps on all of your intake and vaccum pipes.. had the same prob when doing my conversion and I had missed 1 intake clamp and 2 others elsewhere in the vaccum system. Any diagnostic codes coming up?

[triptek]

Anyone know how to test the tps.

The coil plugs are pretty stuffed, can they cause that much of a problem? It even has the problem when ya rev it up under no load.

[Cuzzo]

TPS : You will need to find a workshop/engine manual.

In there should tell you what resistance the TPS should be when you test the pins with a multimeter.

[JP]

I accidentally stuffed up the TPS wiring when I did the 1J swap on my chaser, the IDL wire was grounded which induced a 4K revlimit.

[Endless]

Anyone know how to test the tps.

The coil plugs are pretty stuffed, can they cause that much of a problem? It even has the problem when ya rev it up under no load.

Had almost exactly the same problem on my bros soarer, did not want to go above 4krpm which about 15psi on his setup, felt like it was hitting some kind of cut - replaced coil pack plugs and resolved problem.

For the record 2JZ ones are a direct fit and are a lot more robust.

[Dieseltrain]

Coil Packs are a Killer!!! Mine wouldnt rev Over 3500 and even missfired at idle and low rpm driving..

I race my car alot, so i bought brand new coil packs ! I dont wanna be stuck somewhere 1000kms from home with that shit again!

Next time out, it ran almost 2mph more and ran 0.05 better ET with 1psi less boost on board from its Previous Best

[SL666]

I'd check all the vac lines are going to the right places.. there is a couple of outlets that don't let boost go through, if you have the map hanging off that it won't be real good.

[lojik]

I had boosting / misfiring issues with mine for a while.
Pulled the coilpacks and found they had plenty of fine cracks, bit of epoxy and electrical tape sorted em out nicely.

oh and for the record, all of my coil plugs are missing/smashed, runs fine that way.

[triptek]

Thanks for all the help guys. Still no luck in getting it running so i'v gave it to my mate, he's gonne put it on the dyno in the morning and check the afr's.

[ripfast]

i have the tps information somewhere at home i think but u could check by starting the car and then loosning the tps and twisting it to see if you can get a better idle, just make sure you mark the orginal position in case something F%^&S up.

just a suggestion

[Dieseltrain]

Moving the plastic section ( body) of the TPS wont gaurantee you get the same Voltage once you put the body back in the same place!

Check the voltage beforehand, record that. Then move it round. If not successful, move it back to where the correct voltage is or was.