1UZFE runs great without AFM

[extractors]

Hello fellow Lexthusiast's,

I will cut great to the chase, I have a 1UZFE in a 76 s class mercedes.
The donor car was a 1994 Celsior/ls400. Its running std ecu, and 4 spd trans.
Now when I disconnect the AFM, it runs great, heaps more power through out the rev range, heaps more torque and punch down low. Only problem is it runs well rich, and has a 5,500 rpm rev limit.

Now with AFM connected, it turns into "dog mode", absolute slug, at anything under 3-4k, you really have to work it to do anything. Once you get it on the highway, it does seem ok, not great just ok.

Now for time being Ive rigged up a switch, so I can switch between AFM, and no AFM. When the switch is flicked, there is an instant urgency with the car, when its set to AFM again, "dog mode returns"

Now, Ive got two ecus, and neither are throwing fault codes. Once ECU is a MiNeS ecu, I even went to the trouble of sending it to Japan, to have the once over. They said it checked out fine.

I have tried 3 different AFM'S, I have a V8 soarer aswell, so can easily swap parts around. The V8 soarer, goes very well for a stock v8, and I know the afm on that is working a ok, and pulls nicely on the dyno.

The car in question has the following.
New timing belt, idlers, pulleys, bearings, seals, water pump etc

New rotor buttons, dizy caps, leads, platinum ngk plugs

New (aftermarket coils)

Original igniters.

New 4 wire O2 senors ( have checked voltage output, including heater wires, and all checked out ok)

Custom headers, twin 2 inch into single 2.5 inch exhaust, no cats.

Ive set up TPS to factory specs,

set idle, cleaned IACV, checked for vacumm leaks, replaced all vac lines.

New water temp sender

Ive checked compression, 180-182 psi on all cylinders

Done several upper engine cleans, injector cleans etc.

Car is running a factory mercedes, 094 Bosch external pump.

I'm really out of ideas now ??

Is there anything I'm missing here ?

Brett

 

[sideshow]

Wire up a diagnostic plug and put a scanner on it
Otherwise I'm moving to South brissy in a week
If u want someone to look at it but fixing and solving
Silly issues like this can be a fluke and fixed quickly or
Take ages and get expnsive
So it depends how desperate u r
Does the ecu light flash at all when u check for codes

There is no fuking way anyone can check and ecu properly
On the bench. U really need to plug it into another matching perfectly
Running car

Anyway pull ecus apart and check capacitors as I've bad this prob
And it was ecu capacitors

 

[gloverman]

Getting some live data is definately the way to go. I had a vehicle with a similar issue just the other day. I found the broken earth wire to the AFM by mistake and then found that the TPS wasn't reading correctly - turned out the TPS was fine but the ECU was the issue. I wire a diagnostic port to every conversion I wire. Cheers

 

[sideshow]

hey kelvin i dont have enough of the half moon diagnostic plugs to do that
most my 1uz mail order looms never have them
do u get them from other cars

 

[extractors]

Sideshow, I actually sent this loom to you, and as far as I aware, that side of things is a ok, well you are the best in the business Its great you coming to QLD, and I sure will drop by if need be, I can get you to wire in a diagnostics port if need be.

Ive replaced all the caps in both ecu's.

I ran a check light, from B+ to W in the diagnostics port. When I disconnect things, the relevant fault codes come up. then reset ecu, and the fault codes just flash continuously.

Gloverman, Ive checked the AFM according to the manual specs, all seemed fine, even compared to another one at same time, specs were pretty close from memory.

Ive tried two different TPS sensors, and reset it, and throttle plate according to manual, and all seemed fine, different sensor had no noticeable effect.


I actually just got back from a drive, I ran it with AFM signal connected. Now the car was cold, and seemed quite good actually, really lifted. Now as soon as she warmed up, loss of power. So I had to resort back to running without the AFM signal again.

Now I'm aware of the slight decrease thats usual when warm, but this just seems way to drastic.

I really think the ecu is pulling way to much timing, Ive had it one the dyno ages ago and the AFR's were into the 11's so plenty of fuel there.

So what can pull timing, Temp sender, Ive replaced that, water temp seems good, sits around 80 degrees, runs pretty cool really, radiator been serviced, has new genuine Toyota thermostat.

What about the intake air temp sensor ? I know some of the LS1 guys have issues with this, can this sensor effect timing that much. Could the AFM just be getting cooked in the engine ?

Brett

 

[sideshow]

i dont really trust many ecus which have had capacitors replaced
but if u can find a car to try yr ecus in that would prove if they r good or not

ive only had 30 to 40 % success rate in the ecus when replacing caps
this is y i dont do them often as i say its 50 bucks whether they work or not
were the caps in both ecus bad or did u just replace them just for safe keeping

if u have the ls400 / celsior ecu with 4 plugs 2 rows each and 4th plug is 5mm
over and up side down then i have spare ecu if u want to try it in a week

air intake sensor is in airflow meter

 

[extractors]

Sideshow, MiNes stated that the "condensors" as they call it, may need replacing, and that was going to be around 250 bucks aussie, so I just did it myself. Some of the caps in that ecu were a bit tired looking, but not terrible.
The stock toyota ecu looked about the same, and as you say, just replaced them as a matter of course.

Now the original ecu I had just died, car used to stall occasionally, then one day just stopped and wouldn't start. I sent that ecu back and have the current one.

Yeah I was thinking the AFM, maybe be getting to hot, and causing timing to be pulled ?

Sideshow, did you ever wire up the xede ecu to your hilux ? just wondering if all else fails, maybe I should go this route, and just wind in more timing.
I know this is not really orthodox, and to some degree I agree, get it running properly first, then tune, mod etc.

 

[sideshow]

if u dont get it sorted in afew weeks give us a buzz
im coming to south brissy next tues/wed but wont have my tools
then i come back to sydney week after
then week after that back up there for good
we r 5 mins from movieworld

 

[extractors]

Ok, thanks for that,

And regarding the ecu, I think the one you have is the earlier series one ecu ?
perhaps not. I'll just check

 

[extractors]

34 p 22 p 16 p 28 p

I'm pretty sure thats the pins, or thereabouts.

 

[sideshow]

ok mine ecu is wrong one
i would first fix std ecu running before doing mods
i never got the exede was about 1 grand plus a tune
im not a fan of air flow meter signal changing aftermarket ecus
did the ecus have the same issues before u did the caps
its prob not the caps or ecu some probs point towards ecu problem

 

[Beezer]

would it be a bad knock sensor?

 

[extractors]

Yeah it was the same with both ecu's before the caps.

Beezer, I not sure of the knock sensors ? but when on the dyno it showed no sign of knocking, just down on power.

When its really dead, you can basically hold it in first gear, floor it and it just makes alot of noise, eventually revs out and goes, but real lethargic.

Could disconnecting the afm effect anything else. I remember reading that disconnecting it allowed you to run the car even when one of the coils were dead ? But it definitely has a big effect on timing.

 

[extractors]

Ok, so Ive been driving around the coast a bit lately and its been quite warm.

Car runs great when cold, and as soon as she gets hot, the power goes.

Now as far as I can tell, it aint a water temp issue, its generally steady as a rock and sits below 82 degrees most of the time, it will creep up in traffic, and then the 16 inch thermo fan kicks in, and down it comes again.

Now, the afm, an airbox are just sitting in the engine bay right behind the headlight. there really isn't any cool air at all getting there. I feel alot of hot air is coming in from the ac condensor, radiator, trans cooler, and alot of that hot air is being drawn in though the intake. That on top of the usual heat soak.

Now my plan is to fabricate a good cold air intake, and possibly shield, or insulate the afm from being "cooked" from general engine heat.

I feel the IAT, is being fed so much hot air that the ecu is pulling way to much timing.

Does this seem to fit the bill, from what others have experienced ? do you think the IAT can pull that much timing to cause the dreaded slug mode ?

 

[8pack]

If the AFM is giving the signal for fuel cut/timing retardation, then your fuel economy should suffer. It's either the AFM is sending an inaccurate signal, or that the ECU is not interpreting the signal correctly.

Put it on the dyno with and without the AFM connected to know the level of performance loss you're experiencing.

Try a piggyback ECU like an EManage Ultimate and get a tuner to correctly set the ignition timing and AF Ratio and see how that affects things.

I strongly suggest you contact Cihan at Etuner, he's great with this sort of thing. He has good experience in MAFless tuning on 1UZFE engines, so he might be the key to the puzzle in understanding the effect of the AFM on the Engine's fuelling and timing.

 

[extractors]

8 pack,

I'm running a EMU on my 1J, not tuned yet though.
I have looked into this for the 1U. It does essentially eliminate the IAT which removes some of the issues with ignition pull with air temp increases.

 

[8pack]

Go the EManage Ultimate. Have a chat to Cihan for some advice too - he's good with this sort of thing.

 

[extractors]

8pack, I think the EMU is a really good unit that should give equal to standalone performance, without alot of the head aches. So yeah point taken, have been thinking along those lines for a while. Hopefully Cihan will be in QLD in near future.

Wiring the EMU should be interesting to the Celsior ECU ?? I have pinouts for all the soarer ecu's, and some of the main signals on the celsior ecu, but far from comprehensive. I know I can use continuity test's from engine to ecu, so might have to do that, but it is a real pain.

If I do it, I'll get a patch harness, wire it on a bench, so it will then be plug and play.

 

[8pack]

The EMU is a great piggyback unit and you can pick them up for a good price from America too.

As for the wiring, it will be a little different from the Soarer, but not so much so that it'll be a headache.

 

[extractors]

8 pack, yeah last one I bought was from Germany, about half the price of aus.
I don't touch second hand ecu's though.

The ecu, I will be wiring it to is a series two celsior, I had a look on the net last night, and now have all the pinouts. It looks pretty easy, group injection, so 4 wires there, and 2 ignition signals.
I'm not even sure if it is worth getting a field harness or similar, there really isn't that much wiring, its more for easy removal etc.