won't start warm

[polar765]

I recently swapped a 94 mazda 4.0 into a 93 ranger ,which also had a 4.0 ,also used the 94 autotrans ,we changed the engine wireing ,the plenum ,the sensors from the 93 ,replaced the 94 egr exhaust with the 93 exhaust ,new o2 sensors ,did a fuel pressure check with a guage ,replaced the coil pack to the 93 ,so everything is now 93 ,the engine starts instantly and idles then goes through a rough idle but then smooths out and is driveable ,seems low on power ,once the engine is warm it will not start ,it cranks ,the fuel pressure is 35 lbs and there is spark ,starting fluid doesn't help ,once it cools off its starts again ,have tried both temp sensors ,both maf ,both idle control modules ,throttle position sensors with the same out come ,there are not any codes in the computer even after driving for about a half hour

 

[turboranger2.3]

if there no codes. its a guide line generally.

ITs not computor related.

 

[shane96ranger]

Out of curiosity, have you tried both crank position sensors? Also, does it ever start when it's warm (I mean after cranking for a while)? Does it smell like gas? I just had something similar happen on my Mustang and it was the fuel pressure regulator. It would start leaking gas into the vacuum line so when I went to start it all the gas would get sucked into the plenum and flood it out. It did eventually start though....and stunk like gas afterwords.

 

[turboranger2.3]

any sensor out . will set a code. NO LEAN CODE . NO RICH CODES

REPEAT CODES , IT WONT ALLWAYS TALK TO YOU. 3-5 TIMES

DONT BE SHY TO REPEAT ANY TEST.

RE -CHECK YOU CODE READER

WE RELAY ON THE ECM FOR DIAGNOSTIC STRATERGIES


IF IT DOSENT COMMUNICATE . WE ADDRESS THAT ISSUE FIRST

(NO CODES OUT PUT)

YOU HAVE TO FIX THAT ANY WAY FOR THE FUTURE

WHEN YOU SAY NO CODES IS THAT CLEAR OR NO CODES AT ALL.

 

[polar765]

no codes at all ,just replaced the fuel pressure unit ,have changed the icm ,iac ,and crank sensor ,checked a spark plug and it was dry ,went through the connectors again ,started but it was because it had cooled off ,once warm no start just cranks

 

[turboranger2.3]

Forget the game of diagnostic darts

we need a logical approach.

We must get communcation with ecm.

Its smarter than us , all modern system are design to be self diagnostic

with out communication (you will bust your balls!!!!!)

it was never design that way,

alldata on-line manual $26 a year

you might need a wiring diagram. To attack logically .


Alldata you will have everything. Flow charts for no codes output

 

[shane96ranger]

Have you measured to see if you are getting pulse at the injector harness? Almost sounds like a wacky ECU.

 

[turboranger2.3]

verify clear codes 111. have communication with ecm

or no codes - no communication with ecm

 

[--weezl--]

is this a used motor, or a rebuilt motor (i realize it's a 94)

reason i ask, we built a race motor and had the exact same problem, it didn't have the power it should, and wouldn't start once it was warm, it turned over but wouldn't start, what it turned out to be was when we did the cylinders, the pistons we used (or rings, i forget) were slightly oversized, because it was rebuilt, and the motor was overbored, (again, just a little) not enough to really mention, as it didn't make a significant displacement difference, but it was still done. and the problem was that the pistons were too tight in the cylinder, when it's cold, everything is contracted and the spaces are slightly larger, but when it was hot, everything swelled and the motor would turn, but the starter couldn't quite get it up to speed for the ignition to catch. The difference in crank speed was almost unnoticeable, and had we not realized what the problem was, we wouldn't have noticed...

you said it cranks, does it fire at all? like even once every 2 or 3 turns...

 

[fivespeed3.0]

I had a lawnmower with that problem, turned out to need a valve job. When cold, the valves would seat, when warm, the valves would not seat properly, and hence not enough compression. You might want to check compression when its warm.

 

[polar765]

won't start

son in law figured out the ecm was bad ,he put the mazda ecm in and it started every time ,finally gives codes but since its the wrong ecm it gives codes for egr but 93 doesn't have the egr so be looking for a good f37f -xb

 

[turboranger2.3]

heat related. tap test , forgot . while cranking hot ,tap ecm. . try it,

I'm sure it as a EGR. it the law. or did you take it off.

Once put an eraser under the lid of the ecm.and closed it, the little bend in the curcuit

closed the crack and he got 100 mile to home and 2 month.

the ecm as cold solder cracks. on one of transistor drives. or transistor is toast.

fix them all the time.

powerful magnifier. I use a 12X jewelers eye peice /looking for tiny crackd around solder conn.

Just for fun. open it up. all transistor drivers. are on a heat sinks.
there large servicable unit.look with powerful magnifier, if you want.

re-man ecm , that what they do .they dont go into the micro curcuit.

drives, are at any electronic store.

I do this all the time. my favorite , BMW. temp control unit $1400 + labour

i'll do it for $600 a $20 part and 1.5 hour work. scanning and diagnonsis included

customer is happy. but they leave the car for the day.

GOt TO PAY THE GURU'S, THE BIG BUCKS, TO SAVE MONEY.

Did we learn. Get communication with ecm
get codes
follow flow chart.
test before replacing any part (if you can)


And you won't have a shopping list of parts(diagnostic darts)