1uz running rich/ rough

[KLR16V]

yeh i had a look at all the vacume lines but they all seem ok. i also sprayed crc around the engine but i didnt notice the revs going up al all.

[crownv8]

Might be a long shot but I had an EFI Ford years ago doing a similar thing and the diaphragm in the fuel pressure regulator had a hole in it and it was sucking fuel straight into the manifold.

Could be something as simple as that. Just pull the hose of the regulator and get a longer piece of hose and give it a suck. If you get a mouthful of fuel that will be your issue.

[KLR16V]

i bought a new AFM yesterday and installed it.
its made the car much better. no more missing or hesitating.
Also feels like a new motor, its got so much power than before


BUT im having trouble getting the engine to idle smooth. when its idling it sounds lumpy (like its got a big cam) and is boadering on stalling.

and it always stalls when slowing down while driving, say as approaching a red light.

ALSO, when driving at slow speed its really jerky in 1st gear. and while driving in gear the truck clunks/ jolts when u get off the throttle, and when the throttle is pressed in again.

[dumbass]

check power to idle motor and also check if its stuck shut

[KLR16V]

idle motor has got power to the 2 middle terminals. how do u know if its stuck?
I'm thinking about buying a mates dead 1uz motor and swapping all the sensors and coils to my engine and see that fixes it

[4th surf]

The coil on the L/H cylinder bank (the one mounted above the A/C compressor) tends to break down under load when hot. This in turn causes poor idle esp when coming to a stop and also a missfire under acceleration. Effectively you loose 4 cylinders. Also spare a thought for dirty injectors as I went thru all of this with mine last year. 2 new coils and serviced injectors later she drove like a new car. New coils are readily available from Repco and the like from about $60 each, use what is listed for a 1990/90 Lexus LS400. Do yourself a favour and throw a new pair at it. Given the other problems that you've found which are all contributing factors these and a new set of leads are the last things left. Remember they're likely 20+ years old now

[KLR16V]

il buy some coils first thing in the morn. hopefully thats its. it does seem like its only running on 4 cylinders at idle

[KLR16V]

just bought 2brand new coil packs and its still pretty rough.
on cold start up it pisses black smoke out the exhaust and barely idles. give it any throttle, and it sounds like its flooding.

when its warm the black smoke stops and it runs a bit smoother and it goes alright when driving normally.

it still stalls when coming to a stop while decelerating.
accelerator is still touchy/ jolty al low speed.

also i think it is fuel cutting under load about 4000-5000 rpm. (im not sure on rpm because i dont have the tacho connected) but it usually happens at the same point in the rev range. i dont think its a misfire because when it happens the rear wheels pretty much lock up from the engine stopping.


the only thing i can think is that it has something to do with the injectors.
How can i clean them/ check they are working properly.
Does a 1uz have a cold start injector?

[nathanshnoz]

Does a 1uz have a cold start injector?

depends on year and what car it came out of.

Do you know what year and model the motor came out of?

sticking some good old injector cleaner in the fuel tank helped mine run a bit better. alternatively you can remove the injectors and take them to be cleaned professionally i think from memory its around $10-15 each depending on where u go

[4th surf]

Nath the way to find out is from the part number from his ECU and we are looking for a number like 89661-***** as that way the model can be identified and some of us with some knowledge can try and work out just WTF is going on. The basics have been covered so now we are looking into more diagnostics and this could be a bit of a challenge depending on how it was wired up. Aside from replacing O2 sensors and also the ECT sensor which the latter being a known problem there could be a DTC logged with out which tails are going to be chased which seems to be the case right about now

[KLR16V]

I finally figured out what the problem was.
I borrowed a mates MAF and my engine was all good. goodbye miss fires and smokey exhaust

So The MAF the wreckers sold me was a dud. bastards!!!
If only they sold decent parts i would have had this sorted out ages ago

now ive gone to the trouble buying new coils, and a spare 1uz engine to get the sensors off... which i didnt need in the first place.

If anyone is interested in 1uz parts pm me. Ive pretty much got a whole motor

Thanks for all ur help guys. appreciate it