random mazda truck ?

We may earn a small commission from affiliate links and paid advertisements. Terms

reckedracing

reckedracing

TTIWWOP
VIP
so i got a 91 mazda B2600i 4x4

fuel injected

problem is that it runs like shit when cold, but then runs fine when it warms up
5 minutes for warm up approx... maybe 10

if you TOUCH the gas at all it kills the truck

checked coolant temp sensor, and intake air temp but they are within specs...
no check engine light...

i have no idea what else to check, tonight will be fuel pressure, but fuel pump is less than a year old...

figured maybe someone would have a diffrent idea for me to try
 
disconnect 4 wheel drive(front drive shaft) and load a 13B in that thing......
kinda like my friend who put a SR20 in a Nissan pickup truck.
 
what thermostat are you running cold or hot? run a hotter therm
 
well, thanks for the advice but it has nothing to do with the thermo...

starts when cold, but you cannot touch gas until it warms up or it will stall

once its warm it runs fine...

so new question... i know with hondas if you unplug your o2 for example you will get a CEL, but with this truck i can unplug everything from coolant temp sensor, air intake sensor, o2, mass air flow sensor, unplug everyhting and it doesn;t alter the idle OR THROW A CEL...

i am completely baffled, something tells me i need a new ecu... any opinions?
 
Even though it's fuel injected, it still has a choke. I'm willing to bet the choke isn't operating.

When you start it, does it have a fast idle ? It should be idling at 1500 rpm until the needle hits "C", then it should back down to a regular idle.

The temperature sensor, the one on the Intake manifold (Usually near the waterneck) may also be malfunctioning. The result is also going to be a slower performing truck. On the cooling path, somewhere in the intake plenum, is a single wire sensor. This sensor operates much like an O2 sensor in the way that you will diagnose it.

At full hot, it will put out a voltage of like.. .45 or less. Check your manual. When it's cold, no voltage at all. It's a bimetal switch, so if the sensor has been exposed to BarsLeak or something like that, it will be damaged and possibly not working. $5 part.

If you can (It's not too cold for ya) remove the air pipe, and the throttle body and grab a good flashlight. Peer into the upper intake plenum, and you should see a bunch of coked up shit on the metal. Make sure that gunk isn't blocking your cold start valve (The CSV is a line that goes from your fuel rail to the upper portion of the intake manifold plenum. It's only on when you're turning the key and the temp sensor reads cold)

Then we're going to check your throttle position sensor. Write back and lemme know what you think of this. (Edit: Not Throttle position sensor, Crank Angle Position sensor)

-> Steve
 
hey
thanks for the help steve, but i went through all that testing electrical sensors for ohm readings and such...

so, finally figured out what the problem is, and it has some relevance to honda auto computers too...

so, mitsubishi made the computer for my truck, as well as many other vehicles around this same time period... same components used in honda automatic trans control units...

so the problem is for mitsubishi ecu's/electronics made from 89-95 approx... they used shitty capacitors that had plastic seals on the bottom, over time the plastic seals shrink up allowing the acid inside them to leak out, then the acid goes into the circuit board and starts fucking up all sorts of shit...

so i sent my computer to foreign computer repair in florida, and i got it back within 5 business days approx, they overnighted it back to me the same day they got it in and serviced it...

so i put it in the truck and it starts right up now...
if you ever experience this problem some clues to look for are first a fishy/seafood smell, no idea why, but when they go bad they stink like rotten fish, i always wondered why my truck had that funky smell, another thing to look for is corrosion on the circuit board, both on the top and the bottom...

the company did some nice work, not as nice as lets say avpro, but aparently they fixed the capacitor and soldered in connections to bypass all the places the circuit board was damaged, so they get a good rating from me...

total cost was 195 for repair and return shipping and something like 13 bucks for me to USPS priority mail it with insurance and delivery confirmation...
compared to 350 ish for a new reman ecu from napa or auto zone i think this was a decent deal...
 
You must log in or register to reply here.
Back
Top