I have a 83 recaro T/A. i have recently rebuilt the motor and replaced everything stock except the cam. I installed a crane RV cam with a 455 lift. The car runs very erradic and will idle up and down on its own. The Injectors TBI'S are flowing good and there seems to be no known electrical faults according to the computer test codes. ECM shows no faults. The plugs r45 were not hot enough and i upgraded to double platinum plugs. New coil cap rotor plugs and wires. The tach jumps erradically and all system and ecm grounds are intact. Someone at the parts store told me that he had a vette with cross fire and upgraded the cam to create the biggest nightmare he ever contended with. If this is true what can i do to smooth out this beast and get a fairly smooth running machine. It wont idle properly in gear. 700r4 automatic. People have said you need to reset your prom? What is the prom and if needed how do i accomplish this? Help HElp HElp

 

You don't give cam specs, but any cam described as 'RV' won't be big.. I'm guessing you may need to balance your TB's. Come on over to the Crossfire forum for all the info you need...
http://www.crossfire.homeip.net:81/cftest/default.asp

 

plugs were not hot enough? do i read that as rich? i would data log and determine if that cam is making you rich on the idle or low MAP.

 

The CFFI ECM is underpowered. The CPU is to slow to make corection calculations if the motor is not stock, and it does not have enough RAM. A company called Turbo City modifes later model ECM's to work with CFFI.

 

you could use turbo city unit. but i think most of us run the 7747 modified for stock wire harmness. i thgink comes out of 89 or so truck. mine was a v6 astro van. geekybill on crossfire forum modified mine and set me up with starter chip so car would run. i think was under $150. not sure on that.

 

The 7747 and the Turbo city unit are the same thing, except the turbo city unit costs WAY too much, IMO.

But the computer isn't the problem. If you'll scan my sig, you'll see what can be done off the stock ECM. Take a look....

Ben73 is right that the cam isn't the problem either. Again in my sig, see the cam I'm running.

You either have a vacuum leak, improperly balanced TB's or low fuel presure/weak fuel pump. Those are the same old simple problems that always seem to come up. Easy fixes.

 

possibility you need tuning as well !

 

I am new to this crossfire injection and The ECM problems that may arise in these f-bodies.... however for further information to all who post replies and I do appreciate the help. Heres more info

I rebuilt the 305 with .30 over new thru out with all original (not rocker rollers or anything outragously high maintenance or high dollars). The parts store had a crane RV cam and lifter set cheaper then replacing with stock milled cam so i upgraded the cam and cam only. The exact specs shouldnt matter that much as it is just a step up from the stock cam however the TBI's spray fuel evenly and pour it on when requested. The idle is crazy and the tach jumps around from 3000 to 6500 regardless of the RPM. Could be Short circuited or flawed or even trashed maybe? But it will settle to three to four thousands every once in a while and the idle will run at approx 1400 smoothly but cuts out like crazy when put in gear. I have received map sensor error messages from the ecm but am not sure what to check for that. The book shows the flashes as reading MAP but the troubleshooting guides leads all symptoms to ECM/Vacuum/timing but not specific fixes for any. All it wants me to do in the book is have dealer service it. Hopefully You will all understand I wont let a Dealer rake me across the coals for a five dollar adjustment or fix???? I dont want to have to go buy a super chip or prominator,or turbo city stuff,,,, if it can be avoided. Any and everything has been replaced as far as timing goes and all is still erratic. Does anyone know the web address with schematics to the 83 T/A's vacuum routing. I have a mess under my hood and want to get it right??

 

I'd like to welcome you to the TBI & Crossfire arena.

As for the tach jumping this is something that needs to be dealt with first. A jumping tach is symptomatic of an ignition problem. It may be the ignition module, pickup coil, or ignition coil. May also be a loose reluctor on the distributor shaft.

You really need to prove/discover that the ignition system is up to par. A shops ignition scope would be great, swapping parts with known good one can be good. Double check all grounds on the vehicle.

Swap in another known good tach. It comes down to isolating and fixing the tach bounce, then going from there. It is saying that something is wrong.

RBob.

 

sounds just like my 83 CFI with the same set up bored over thirty crane cam lifter and rockers.(2030 comp cam I think). I do have 350 heads and intake from a vett though. My idle is very rough and will dye once the car goes int closed loop unless I diconnect one of the IAC or hold my foot on the gas pedal. First thing is get a higher pressure fuel pump and new filter. The CFI will run on no less than 19PSI. As for the vaccum routing look at the sticker under the hood and follow it carefully unsing new hoses as the CFI does not like vaccum leaks of any sort. Use stock spark plugs unless you hae upgraded you ing system splitfire ect... plugs will do more harm than good. I will be glade to help out is any way I can as it is hard to find help on these engine at times and not may people want to fool with them.

My car came already apart and boxes so I can understand what you are going through.

 

This is not correct. Stock should be between 9 and 13 psi. I have set mine to 15psi and it runs very nicely.. 13.7 at 100mph and a nice 12.5:1 AFR under WOT on the dyno...

 

The proper fuel presure for a stock engine IS 9-13 PSI as Ben73 stated. The above statement about 19 PSI is outright false. Disregard it. Also any brand of properly spec'ed spark plug will work fine. As long as it is the right "model" for the application, it'll work fine, so don't worry or waist your time on plug issues right now.

RBob is also right about your ignition system. If the tach is jumping around the way you stated, something is not correct in your PRIMARY ignition system

You need to diagnose the ignition system issue, and get that fixed first. Also, do you have your Map sensor hooked up properly? To the correct vacuum Port? Did you check your fuel pressure? Figure out the ignition problem and let us know what you found, then we'll move onto the next step from there. I am quite certain that what ever the problem is, you will find that it is very simple and basic. There is nothing "magically" complex about the CFI system.

 

BEN: you are running 90 lb injectors at 15 LBS ? i was at 12.2 AF at 5100 rpms at 9 lbs FP with 90 lbs injectors. i was gonna bump up to 10 lbs to see how that your work next spring. but 15 lbs? WOW.

 

Ronny, I too am running 15 PSI at WOT, although my injectors are "rated" at 75pph. They are MSD brand and I don't know if they are rated the same as GM units or not. I do have a VRFPR that pulls out FP as vacuum increases to give me 10 PSI at idle, with my combo, and my elevation. This was done to "cure" and over rich condition at idle, which resulted in intermitent stalling at stop lights. The 15 PSI FP was chosen because that FP yields the best 1/4 mile times for my combo.

I agree with your previous posts that PROM tuning would definitely be beneficial at this point. I'm sure I'd see improved times an deven improved part throttle driveability, but my results are pretty decent, and the fuel economy I see speaks for the efficiency of the combo. More than PROM tuning, I need heads and intake.
-Tom

 

I did not think Ben was running a vafpr due to previous posts on crossfire. i thought he has xram with 90 lbs. i question why he would run 15 lbs FP at idle not WOT. that seems too high if that is at idle. with 65 lbs at idle without vafpr 13 lbs(no less) is considered to the correct FP.

 

I can't speak for Ben, but 15 PSI at idle made MY combo want to flood out when coming to a stop, and pushing the clutch in.

15 PSI does SEEM high for idle, especially with 90 pph injectors, but you have to feed each combo what IT wants.

 

Tom
What spring are you using in the vafpr?

 

I dunno.. I have a definate ignition problem as tom and others have pointed out.. The distributor is probably worn out and has bad capacitors and the like. I will replace and update my Crossfire friends soon.... MAy cure all the issues... I hope
I have no idea of the vAp springs and all the details.. its all stock and wasnt running when purchased.... It will prrrrrrrrrr one day and i will be one happy camper..
Terry
the reluctant rookie recaro owner

 

Dan I re-used the original green spring that was original to the car. The orange one that came with the VRFPR was WAY too stiff, thus too rich, as you know.

 

i used the green one too but was too lean with it for daily driving rpms. top down solutions sells one between the green and orange to fatten it up a bit.

 

HAAAAAAAAAAAAAAAAAAAAHAHAHAHAHAHAAAAAAAAAhhhhh

 

Do you have a web address for them?

 

topdownsolutions.com ? they are an advertiser on this forum.

 

I'll check it out.

Thanks

 

I'm a little late on this thread -

I had minor "jumping" of my tach after my rebuild - I started to suspect the distributor, and replaced it with the msd small cap (#8366).

This cured the "jumping" and smoothed out my mid-range. I believe the distributor gear was worn, and it didn't mesh nicely with the new cam gear.

 

I have been amazed at the answers in here for my problem but i beleive that i was told the ditributor is the first place to look and i will ...as soon as i can replace with a new. the dist did jump upon initial firing. my fault. and it hasnt been great since.. probably tore the gears and capacitor out or something.. anyway it is a project car and with xmas here it can wait a lil longer thanks for the post

 

hey guys


he stated the he has had the engine out of the car. I run into a simliar problem on a tbi blazer and it turned out to the the ecm grounds on the engine was not connected.