I Don't have Ramcharger but decided to post here because I know you guys are knowledgeable about TBI
I bought Dodge b250 few months ago, it's 1989 TBI 318 and I'm spending a lot of time trying to solve his puzzle.
my 318 have big problem with Idle RPM and throttle response.
Idle goes up and down about 100RPM, it happen suddenly and quite often.
Other thing is that it have huge lag/bog when I hit the accelerator pedal(under load engine dies) and backfires ( without doghouse and air filter it could burn eyebrows and scare to death...) everytime engine come back to idle it goes a bit too low, 400-600 RPM before ISC react.
What I did :
- Disconnected ISC --> No difference, so ISC is just doing corrections and it works.
- Cutted exhaust pipes after manifolds(before it had single pipe with lame catalytic converter) --> and it helped, engine is not dying anymore, can't see any backfire and it sounds great! still have other problems
- Different ignition advance setup --> No difference
- Changed spark plugs(gap checked), and all of them are getting good spark
- Throttle body disassembled and cleaned several times and it wasn't as dirty as I was expecting, new gaskets, --> No difference
- Cleaned all vacuum hoses and solenoids, sealed vacuum tree --> No difference
- No fault codes after keydance (12 55)
- New fuel filter
- Cleaned computer, connectors, checked for good ground
- New engine oil and filter
- Have been running with injector cleaner in fuel
- Checked fuel pressure, it stays strong at 14,5 psi even at road test when i was forcing it to stall
- Checked other mapsensors(including GM) and their voltage --> No difference, at least not I was looking for
- Injectors have 1.8 Ohm resistance
- TPS checked voltage, don't remember what it was but was changing in proper range
- Tried to look at injectors spray pattern, it's cone shaped but I don't have enough experience and good strobe light to determine what i see is good or bad, I'm also not experienced in searching for vacuum leaks.
- EGR I think is not working, it have completely rotten cap(I can put finger inside it), plugged vacuum hoses, tried to remove it but these bolts are welded !!
Already removed Air pump, cat, air conditioning, changed fan to electric.
It's not a daily driver or work horse and I want to wake up this motor in closer future so I consider carb conversion.
My last mileage was 10mpg with 70% city driving and cast iron right foot, I don't know what numbers should do TBI in good condition.
I had before 2 cars which were EFI and my experience is that it's much easier to get used to the problem, drive it and sell your fuel injected problem to someone other (it doesn't mean that did nothing to solve it).
I'm asking all of you for help because I'm running out of ideas.