Gevo

Hard to say. I assume your timing is correctly set? You can try to see if it's due to a really rich condition by setting your vafm to 5 or so clicks lean and comparing performance with before. I know with the orange flamethrowers, I was at 11 clicks lean before it worked somewhat properly.

RJR

Have you checked the TPS? The TPS is an important component in providing stability in the engine control loop. It anticipates the needs of the engine by providing information to the ECU about throttle position changes. That allows the ECU to react early instead of waiting for inputs from the VAFM and the O2 sensor. When the TPS signal is missing or wrong, the ECU is late in responding and is essentially playing "catchup" to the VAFM and O2 sensors, resulting in poor driveability and unstable control of the engine.

The other issue, of course, is that you have a nonstandard VAFM and nonstandard injectors. The ECU control loop is carefully tuned for the components that Toyota installed at the factory. When you change those, you essentially are redesigning the engine control loop, but without any of the mathematical models and analysis and measurement tools that the Toyota engineers have at their disposal. Control theory is arcane and hard enough when you have all those tools; without them you're pretty much in the dark.

In particular, if either the VAFM or the injectors have higher "gain" than the stock ones (in other words, more fuel per millisecond of "on" time for the injectors, or more voltage change per volume change of airflow for the VAFM), the control loop will move toward instability. The ECU may be able to handle changing one of those components, but both in combination could be pushing it over the edge.

chefdave

Hi
Thanks for more guidance will search for how to test tps. As for setting leaner took mine back to stock setting as set by toyota could not get engine to run turned over but would not fire. So went four clicks rich any more and exhaust fumes makes my eyes water. Will post results as i get round to testing them. Mpg still seems to ok as getting 230-250 miles on a tank of fuel which is alot better than 120 when i first got it. Acceleration has confused some drivers when coming out of a 30mph limit or going up hill. As they expect snail like acceleration. My motorhome on toyota motorhomes slogan is speed of parking. Well blown that that theory as im now overtaking tractors on british A roads.

Flame Thrower

hi. back from socal again.

the tan injectors flow within 2% of stock injectors in dynamic (pulsed) testing.

can you smell fuel from the exhaust when its idling?

how do you know that the supra afm is working correctly? any way to test it?

RJR

Thanks for that data point. That should remove injector flow rate as in issue.

chefdave

Hi
might if solved my problem. went to start truck started up fine then went through revs going up and diwn then settled to fast tick over. checked water and pas fluid. lol an behold cooling water is rust coloured must of dislodged a load of crap when i took pendlum off flushed system last year so a little baffled. flush and fresh anti freeze next job.miss i believe is ignition leads. swopped leads from another working car not road legal and managed to reduce miss. ummmmm.
thanks for all the help and advice from everyone. Not the answer any of us were expecting but hopefully this posting will help others.
Will keeping posting up dates to keep everyone informed if prob is now solved.

Gevo

chefdave, so are you saying you swapped in another vafm?

bone collector

yes he did a 7mge swap. hope you have found your problem chef...


I have links to test the tps and vafm if you need them

Gevo

Yea, I got that part, but the last post was confusing if he swapped another one in.. 7mge vafm swap sounded a bit involved..

chefdave, how long did the 7mge vafm work well?>

chefdave

Hi gevo
7 mge vafm is a piece of cake to swop as easy as swapping a standard 3vze vafm. all was going well until i put flame thrower injectors in. the injectors are not the prob believe it is cooling system as i think i had an air lock in pendlum. so no sensors were giving right signals to ecu. driven truck 50+miles today and feels so much better. need to check timing as i had to adjust it to get it to run before. now pinking like hell. going to set it around 12-15 degrees think at moment it is 20+ degrees.

Bone collector would like links for testing tps and vafm just so i know they are not faulty.
Engine even with wrong timing pulls like a train and overdrive comes in at 45 mph instead of 50-55 mpj now i have to watch speedo to avoid breaking speed limits. before it was never a prob as i need a down hil slope and following wind. lol
when sorted properly truck should be an effortless drive with power in reserve.

bone collector

when I switched to the flamethrower injectors I had to go from 6 clicks rich to 5 clicks rich on the supra vafm because I was sending too much fuel to the motor and it was running extremely rich and killing my gas mileage. others on this forum have had the same experience. my timing is set at 16 degrees. I would definitely check you timing to find out where it is set. 20 + can cause damage if you are not careful.


here are the test links I promised.
VAFM:
http://ether3al.physic.al/93fsm-mobi...92volumeai.pdf


TPS:
http://ether3al.physic.al/93fsm-mobi...93throttle.pdf


Here is the codes and what they mean. this is a little long but if you scroll down a few pages it shows the codes and where to start looking for the problem.


Diagnosis:
http://ether3al.physic.al/93fsm-mobi...85diagnosi.pdf


good luck and let us know how it turns out.

chefdave

Hi bonecollector
thanks for links will have a check on my next days off. vafm i have turned to 7 clicks rich and feels much better. turned tick over down as well it was running far to fast. think now ecu is relearning and can take up to a week to do this. checking timing was going ok until timeing light connection beyween plug and lead fell apart. cannot use the words on this forum but gordon ramsey would look like an angel.now back to old method run and listen for pinking.

bone collector

Here is another thought for your truck. What spark plugs are you using? What brand, type and gap??? I have found it better to use a hotter plug then the stock copper and also to widen the gap from the .031 to .036 or .038. I only say this to you because you are shoving more fuel and air into you motor then stock and stock copper plugs with minimal gap probably isn't the best any more. This really only applies to people running the 7mge AFM swap and flamethrower injectors.

chefdave

Hi bonecollector
running denso irdium tt16's which i think is the top spark plug to run in this engine. correct me if im wrong. engine is starting to settle but think of replacing everything coil to spark plug. Ie leads dizzy cap rotor arm as i believe most of it is 25 years old after inspection. Plugs are 12 months old and have 15000 miles on them.

bone collector

Sounds good

chefdave

Hi
think i have an airleak or vacuum leak. went to check all bolts again and the four throttle body bolts need another full turn to tighten right up. idle much improved but not right. spark plugs are a dark tan colour. so mix not far from perfect. will buy a spray bottle to fill with soapy water for leak checking.

bone collector

Whoa that's really loose!! You should just take it off and give it a proper cleaning with a new gasket

chefdave

Hi
my throttle body never had a gasket both pendlum and throttle body show no signs that a gasket has ever been fitted. they may of come "loose" as i am now having water running through pendlum and throttle body hoses. Throttle body now goes through a heating and cooling cycle.

chefdave

Hi
yruck is now running better than ever. need to tweek idle to smooth out tick over. when just over tick over engine smooths out and power kicks in. cruising at 60mph is sooo easy and have alot less kicking down on auto box when going up crests. can hold cruising speed going up hills etc not holding up traffic. lol.

chefdave

Hi
do have a vaccum leak on small pipe coming from fuel regulator (?). have ordered vaccum pipe to replace all small diameter pipe. took wife out in truck today and she has a 6th sense on what is wrong might not use techinal jargon but is spot on. idle is over fuelling she told me to push choke in. so have leaned vafm out idle still irratic but smoother. after 3 cold starts idle improving when i fit vacuum pipes see if vafm needs a tweek as the smell of fuel WAS over powering.
I know this is alot of posts but hope this thread will be constructfully useful to other members if and when they need to change injectors. have not lost faith in flamethrower injectors its just the 25 year old parts failing after being disturbed. will get there in the end.