Blue70

Well my 82 crossfire has been in the shop for almost 2 weeks now and they still can't find what is wrong with it!!

You can read about it here
http://forums.corvetteforum.com/show...8&page=1&pp=20

Now I am wondering if I should just throw a carb at it, it's my daily driver so I need it back!

I know I will need.
Intake
Carb
Air Cleaner
Distributor
Gaskets

If I go that far I'll do a cam, lifters, springs, keepers, seals, and timing chain.

The car just turned 60,000miles

Twin_Turbo

Take it to another shop, that system isn't very complicated and any good shop should be able to at least diagnose it. Just swapping parts and hoping it's the end of all the problems is not the way to do it.

Have you tested the ECM? Maybe an injector driver is dead or malfunctioning.

Have you checked the fuel pressure yet,...or the shop did it? If not, they suck and you should go to another shop. 1st thing to do when you have fuel injection problems related to fuel metering/delivery problems fuel pressure is the first thing to check.

Please give an update of what has been checked/done and I will try to be as helpful as I can. Just slapping on a carb is a bad idea, you will need more than just the carb & manifold, you will need a regulator to regulate the pressure down, a vac. advance distributor, the fuel pump must be rewired since prime & run is controlled by ECM on est signal... and it goes on...and on.

Blue70

The shop I brought it to, I took it there because the owner is an electrical whiz. They do all the High end cars here in town, BMW's, Audi's, Porsche, etc. I would not trust any other shop here.
I know he tested all the sensors, (TPS, MAP, CTS, etc) checked fuel pressure, took out the computer and buzzed out all the pins, I'm not sure what was done this weekend but he worked all day Sat on it

EDDIEJ82

TT, my fuel pump works fine without rewiring. I even have the return line blocked off. I know I'm dead heading it and it won't live forever like this but untill I can get bungs welded into the tank for an aftermarket FP it seems to be working fine and supplying enough fuel for the 383. I did have to put a regulator on it.

Blue70 I know what you are going thru but TT is probably right on this one. Unless you just want more HP, swapping probably isn't a good idea. That said if HP is what you are looking for it's not a bad swap email me and I can give you all the details you'll need a few more things than what you asked about and they are very important.

Twin_Turbo

Did he check the oil pressure sender? The thing has an itnernal switch that overrides the fuel pump in case of too low oil pressure, the sender may be bad and you won't get any fuel then.

All those cars you mention use bosch jectronic/motronic derived injection systems, that's a whole other deal than GM EFI. Because he can fix one doesn't mean he knows how the other works.

Ask him what he checked and how he did it.

TPS can be checked for resistance curve and boltage signal return, both have to be linear and no "low spots" should be there, boltage should read from 0 to 5V, 0,525V at idle to close to 5 at WOT
MAP is a 1 bar map and the voltages can be referenced against manifold pressure readings (KPa)
CTS, resistance can be checked at various temperatures and referenced to known values.
O2 sensor operation can be checked by diagnosing the cross counts, even with a simple dmm you cna probe for about 0,46V at idle (warm engine) ...but yours ain't running and that's an open loop problem so the sensor is not the culprit.
EST signal is easily checked, it's a value field on the scanner so you can see what it does. Same goes for the injector pulsewidth modifiers BLM and INT.

Have they checked if the calpac and prom are fine?

CTS resistance table:
Deg F - Ohms
210 - 185
160 - 450
100 - 1800
70 - 3400
40 - 7500
20 - 13500
0 - 25000
-40 - 100700

fuel pressure should be 9-13psi

Map voltage should never read 5 or 0, if it does check the wiring.

Eddie, do you still have the ECM in there? what did you do with the distributor? If the ECM does not see a crnaking signal (rpm signal) the fuel pump should shut down.

2TONE82

Blue 70, I don't mean to hijack your post here but I got to say that TT is, without a doubt the Lars equivalent (and then some) for the CFI system. His knowledge base is amazing!

My car runs great but if she ever gets temperamental I hope I can still reach TT for assistance.

It seems that so many people are modifying the CF set-up that fewer and fewer of us with stock set-ups will remain. I was at a local meet last weekend with cars ranging from a highly modified 65 to an 04, to include two 69 BBs, one a tri-power. A couple of guys were asking about the cross-fire set-up so I pulled the air cleaner assem off and showed them the system while it was running. Outdated as it is, it always draws a crowd...IMHO, keep her stock Blue 70.

Twin_Turbo

When I still had the CFI setup the firing injectors with their visible fuel spray always was good for a nice crowd watching amazed.

Blue70

Ok.
They plugged off the return line out of the regulator and got the car to start, but it dies when they give it some gas. I could hear the car running over the phone but I'm not sure how much gas they gave it to cause it to cut out.
I don't get it, when I checked the fuel pressure myself before I had it towed to the garage I found about 12psi. leaving the regulator and figured it was fine
I will call back soon and see if there is an update.
I don't mind the crossfire system, even though I would like more HP, I just want it to run again

Twin_Turbo

There's only 1 regulator and it's in the drivers side throttle body, the other one has an accumulator. So basically you are saying they disconnected the return line to the tank and made the pump pump against a dead head stop and that enabled the cr to run? If that's the case it will probably die from flooding because the pressure will be too high. That also explains why the TBs overflowed, the regulator must have stuck creating way too much pressure > too much fuel and afterwards the diaphragm would have ruptured. That however does not explain why you got 12psi pressure, it should have been much lower with a ruptured diaphragm. But you say 12psi LEAVING the regulator? Meaning there was a remaining 12psi on the RETURN line? There should be next to no pressure on that line, 12PSI should be anywhere between the pump and the 2nd TB (also on the crossover tube) and not the return. If there's 12 PSI on the return then your diaphragm is definitely ruptured and you have either a healthy pump or an upgraded pump pumping so much fuel that the return line becomes restrictive (12psi worth_.

If someone (or you) replaced the pump with a later model TPI one dead head pressure will be much too high (45psi or so) and that much pressure will cause the injectors to stick open, the pintle willnot be able to close off the fuel flow anymore.
Another scenario that would yield 12psi at the return line is a dented line, check the retun line.

Blue70

OK new twist

I just talked to the guy that's working on the car (instead of the guy answering the phone) He said he is finding 9psi when he checked the pressure. With the return line blocked off it only goes up to 13psi. He said 9psi is the lowest it can be and still be called OK, but he thinks he should be seeing a bit more than 13psi with it blocked off. Does this sound right? He does not want to just go and replace the fuel pump because it's on the low side but still "OK" He thinks there might be other issues, read on.

With the return line blocked off the car will start right up, run and idle, but if he guns it the car will die.

Now for the kicker. His scanner will not read the computer. He's not sure why right now, he needed the scanner for another car for a second so he's not looking at it right now. He wants to be sure the computer is seeing and reading the same as he is seeing out at the sensors, but he is getting nothing when he plugs in.

Blue70

I just wanted to say thanks TT for your help so far

You were right when you said the return line might be blocked, when I took the psi reading all I had for a fitting was a brass reducer I screwed into the return line output and screwed my fuel pressure gauge into it. This blocked off the return line completely. My bad. Thanks for pointing out the error in my ways

Twin_Turbo

yes, it should be much higher than 13 psi against a dead head, around 20 or so. You need a new pump, when the injectors draw more fuel than at idle the pump can't keep up, fuel pressure drops and with it proper fuel metering and atomization > fuel puddling > engine stalls.

His scanner is proibably for TPI cars, he does not have the correct module/software to read the 1225550 ECM.

The CFI only uses 1 serial data output lead and only a 160 baud rate, same as the TPI used up to 89, the later ECMs (Speed density systems 90 & 91 w/ new dash) use a dual serial data connection and run at 8192 baud. If he can scan the older ECMs from the TPI cars he probably doesn't have the coorect software on it since the parameter fields differ for all the different ECMs, also the amount of monitored stuff (sent by serial data) changes.

Do you have a laptop? If so, download WinALDL and build the little aldl hookup yourself (very easy) and read the system yourself. http://www.winaldl.webhop.net/

Blue70

Ok

Just had the pump replaced and the new pump has the same pressures as the one that was just taken out.

Car is doing the same thing, with the return blocked off the car will run untill about 1/2 throttle then act like it's out of gas

wesmigletz

Is it possible you have a clogged sock in the fuel tank, or possibly a hairline crack in one of the fuel hoses?

Twin_Turbo

definitely a fuel delivery problem, somewhere in front of the regulator there's a problem. Check the fuel lines, the rubber lines, the fuel filter (it is on with the proper direction of flow?) the rubber lines at the tank, the accumulator in the front TB, the cross over tube. Also check voltage at the pump.

Blue70

The fuel pressure is holding a steady 10lbs when the engine cuts out. If it had a leak or delivery problem would the pressure drop? After the new fuel pump the car will now start and run up to 1/2 throttle or so without having to block off the return line, so it did help some, new filters and sock were put on with the new pump.
I'm going to have to sell the car to pay the bill buy the time this is over

Twin_Turbo

Disassemble the throttle bodies, something is probably plugged up in there. You can do it yourself, it's very easy.

Blue70

I wish I was at the car, but it's at the garage.
They took the trhottle bodys apart and found one of the upper gaskets was torn a bit, but they don't know if it happend when they were taking it apart or not. They were putting them back together about an hour ago. I will call in about 15min to see what's up with it.

Twin_Turbo

Did they check the little filters and the injectors? If the injectors are dirty you will never get enough fuel.

Blue70

Where is the module that controls the check engine light? There is no check engine light that comes on when you first turn the key on like most cars have, is this normal? Shouldn't the light flash a few times when the key is put in the foreward position? He looked at all your stuff about the scanner (Baud rate ect) and said his should work, but he still can't get anything out of the computer.