i'm trying to keep my 82 running with the crossfire till i have the time to do the transformation, new 350 with carb. anyway its acting up and i cant figure it out. this is what it does. very bad idle and kills. surges at speed. if you take the aircleaner assembly off to watch the throttle bodys,i can hold it at @3000 rpm stedy, you can see the spray pattern on both throttle bodys skip for a split second and the tach jumps around then it will idle up by it self to @4000 then back down then all of a sudden both throttle body injectors go wide open and dump! fuel like there wide open sometimes at idle or even while trying to start the car, but anyway when they both go wide open it automaticly kills the motor. oh and no matter what it does, both injectors allways spray the same pattern. i put a gauge on it and its rock steady at 10psi. even under load like powerbraking it. it hesitates bad under load.
i checked the tps and it was at .480 volts so i adjusted it to .530 like my manual says. i did thr timing and it makes no difference in the way it runs. i checked all vac lines and replaced all the bad ones, no diff.
i'm about to give up on it. it ran the best its ever ran last week. then from one night to the next morning it started running BAD!!!
any thoughts?

 

Well some seem to have pretty good success with the CFI but I've given up. I've even pulled the whole engine for a rebuild but it will go back in as a Tuned Port Injection setup. After buying sensors, gaskets, injectors, fuel pump, IACs, vacuum hoses, manometers, books, and performing a voodoo ritual I could never clear up the idle but it ran out pretty good.

Try http://www.crossfire.homeip.net

Really good site with very smart people trying to help each other out.

 

PS, If I had to guess....fuel pump is going, O2 sensor second and sticking IACs third. You can clean the IACs and check the fuel pressure with a guage.

After much reading if I had to continue working the CFI setup I would opt to add a heated 02 sensor.

 

oh i forgot, i put a new o2 sensor in also. no change.

 

From last week when it ran so good, what, if anything changed? Gas fill up at a different station? New fuel filter? Did you check the bolts on the throttle bodies? Maybe when you removed the air cleaner the stud bolts loosened up?

 

Send a note to Twin Turbo. He is good with CrossFire questions. Don't put a carb on there, fix what you have.

 

Don't give up yet. The cause can only be a few things. First off make sure all the bolts on the throttle body plate are tight. Make sure the bolts on the TBI's are tight. They all tended to loosen. GM put a bulletin out on this. If you notice any difference when you do this even if its not an improvement it suggests a bad gasket. Easy to change.

Next. Check the IAC's. Remove the air cleaner. Look down the triangular shaped hole just above where the IAC's are. While giving the car gas do you see the IAC pins go in and out...they should? Are they carboned up? Remove and clean them.Try unplugging the electrical to them. Any change?

In association with a throttle plate or TBI vaccum leak. Disconnect the hose to the MAP sensor. Any change? Pressure on that hose coming out of the rear TBI should be a constant 19 to 20 psi.

Is your rad full? Coolant temp sensor won't work right without a full rad.

You say you have a constant 10 psi of fuel pressure. no bad. Probably not a fuel problem.

You may have multiple problems. First thing to do is to get the surging under control.

disconnecting these things will cause the computer to throw codes...check engine light. You can reset the computer by removing the fuse beside it for 30 seconds. Or disconnecting the battery. ECM will have to learn again...no big deal.

Remember that when you unplug the IAC's. You will need to drive the car several miles at 35 mph to reset them. Is is possible you did this when the car ran well? If so. Its probably one or both of the IAC's.

Technology seems complicated but its actually quite basic. Its all about fuel, temperature and vaccum. On start up your car run on the CTS and MAP. CTS acts like a choke. Once you hit a certain operating tempurature it switches to MAP and O2.

Have you messed with the TBI's? If you haven't don't at this point. It doesn't sound like an out of balance problem at this point. If you have I'll need to know what you did.

You sent the TPS at .530? No bad...actually good. With the key in car not started attach a meter to the TPS. Get your .530 reading...move the arm on the TPS to full open...what is the range? change in volts???


Keep us posted.

Jim

 

Good idea contact Twin...Thats even a better suggestion then all my suggestions. If he can't figure it out no one can.

Jim

 

Gen 1 ecm computers are crap .. look into a re-man esc/pcm or have a ecm ground problem .. your running problem is beyound a tps .. dont blame the cfi from what you are describing.

 

The vacuum leaks will drive you crazy. I had to reseal everything on the top of the engine to get my leaks stopped. Once I did that it ran an awful lot better.

Bill

 

check the map and CTS, if the CTS connector is loose and making a bad connection the ECm will think it's real cold outside and dump massive amounts of fuel into the engine. Same for the TPS, check the signal for linearity, if there are high and low spots it will give problems.

Any codes???

 

 

Does anyone have a CFI setup that actually idles smooth? Seriously, I'm still waiting on my engine rebuild so I haven't installed any TPI setup but I have heard of only a couple or few that really think their cards run great.

 

mine ran great, even modifed. Idled so smooth you could put a dime on it's side on the engine. Throttle response was great.

 

Mine idles smooth when in park. It starts to go a wee bit rough when sitting at extended stoplights, but never to the extent it acts like it's going to die.

I just replaced my EGR valve which helped. I need to pull my IACs and clean them up next. I do need to recheck all the bolts and verify they are snug (mental note to self).

The engine runs very strong otherwise.

 

thanks for all your help and suggestions guys.
i checked the bolts on both tb's and they were all loose. tightened them up and no diff. its so weird that at like 2500-3000 and hesitating and missing it will all of a sudden clear up and go to @4000 by itself smoothly like its cleared up, no miss at all then just DUMP fuel like a waterfall the next second. it makes me think it has to be an electrical connection.
what is a cts and where is it. i checked the vac hose that comes out the back of the rear tb. the one that goes to something on the firewall with an electrical plug and the hose was dry rotted and leaking so i put a new one on and no change. i unplugged the conector and it wont even start with it unpluged and barely starts with it pluged in.
i removed the dist. cap for inspection and it looked dry and clean, almost new. it doesnt seem like an ignition prob, but i had to check just to be sure.

 

My q-jet idles smoothly at 600rpm

I test drove an '82 that idled as smooth as glass.

 

this is the little monster thats driving me crazy

 

The electrical think at the back is the MAP sensor...it senses the engine pressure...its critcal.

the CTS is at the very front of the engine above the water pump. It should have one or two wires going to it depending on which sensor you have. That sensor picks up on water temperature. It acts like a choke. It tells the ECM to adjust fuel and air mixture. I think I ask this but do you have thermostat and is you coolant fuel. Can't hurt to try running the car with that unplugged the computer should go into default. You may get an engine light if you unplug it but can clear it by pulling the fuse by the ECM for 30 seconds. Come to think of it...you should have got a code when you unplugged the MAP did you?

Check the EGR valve. Common cause of many problems. Unplug the hose, push up on the diaphram and seal the hole with your finger...diaphram should stay up if the EGR is okay.

One cracked hose? Do you have any other cracked hoses???

Just because yuo were able to tighten the TBI and TBI plate bolts doesn't mean the gaskets are good. get a "t" and put it in between the MAP and rear TBI it should read 20 psi. Or if you can get it going disconnect the hose to the MAP...will it keep running?...then attach a vacuum guage.

Jim

 

see that yellow cap under the air pump (left side of pic next to upper rad hose) w/ the black and green wire? The CTS (coolant temp sender) is behind that. Chances are you have the original mushroom type connector one. If so, get a tpi sensor w/ weatherpack connector (so sensor and connector) and replace the original one. keep the original one and that little cover, those parts are hard to find and are the details that make a car complete & original. Looks like you have a nice complete and original one ther, cruise control servo and cable in place, air pump in place, both air switch vavles, emissions crossover tubes, check valves, original lines w/ the original hose clamps, the long fillter neck still there, original crankcase ventilation tube w/ sleeve...

what I'm trying to say is, tinker with it to get it right but don't mess it up w/ a carb, some people will pay good money for those rare parts..just look on ebaymotors, even the smallest items will go for good money. Good, original 82 EFI stuff is getting rare!!!