rexman13b

iTrader: (7)

If the harness is fried, know where I can get one?

fLyiNgOuFeR

i dont know anyone selling one ryte now. but frequent trips to tha junkyard and the parts for sale/wanted section on this forum might be a start. if you wait a while, after i put in my haltch i'll be selling mines. along with alot of other ****.

HAILERS

I still think the secondary injectors are not *opening*, *pulsating*, *coming on*, *activating*, *working*. If the car can be driven past the 3500rpm using light throttle and gradually acheive 80 mph, then that in itself is a strong indication that they are not *working, pulsating, coming on, activating etc* The way I understand the problem is that you stand on the throttle and at around 3500rpm you hit a brick wall and it throws you toward the steering wheel. You can duplicate the same scenario easily on a n/a car. Just take the secondary injector plugs off and go for a ride. Slams you into the steering wheel under hard throttle. There are several ways to go about proving what the problem.At the ECU, located under the passengers feet and with the small plug off the ECU get a digital voltmeter with the neg lead on a good ground and the positive lead on the light green/red wire or the light green/white wire and check for 12v with the key to on. If you have the 12v check and make sure the boost/pressure sensor is connected both electricaly and with a vac hose going to the intake manifold. If you get that far, go a step further and put your voltmeter on the dash and with a long lead to the ECU's small plug(plug connected on the ECU at this time) get on the light green/red wire and go for a drive. The meter should read the output of the altenator, approx 12-13 volts and there should not be a voltage drop until you hit 3500 rpm with the car under load (hard acceleration). The voltage should drop big time down to about seven volts or less. Don't be a victim and just change out parts to resolve a problem. Just in case you don't know, the secondary injectors don't open until 3800rpm, and they won't open at 3800rpm unless there is a load on the engine. Best of my knowledge, the load is determined by what the boost/pressure sensor is seeing. If you have no load, you can get past 3800rpm and keep on reving, using just the primary injectors. SEcondaries will just sit there dormat. If you think its the harness, then just ohm out the wires (but if you do as described above and see 12v at the light green/red and light green/white wires, you've effectively ohm'd the wires out in a sense). The ECU pulsates a ground signal to pulsate the injectors. The 12v is always on the wire at the injectors. I don't have a schematic for a 88 model. If I post the one for a 87 it would be misleading. I'm also making an assumtion the wire colors are the same. If you don't find a light green/red and light green/white wire on your car, well......sorry 'bout that. I doubt the wires to the ECU are whacked, shot, screwed, fried, bonged etc.

2887s

Hey, thanks man! I'll check that next time I'm working on that car.

rexman13b

iTrader: (7)

This car is an 87 T11 so the wires are the same I checked, but if I find that it goes like 7 volts at over 3800rpm what could cause that besides the boost sensor?

Ziggy682

The secondary injectors will fire, even if the boost sensor sees no load. You can unplug the vacuum line, or unplug the sensor itself and the secondaries will still fire at 3800 rpm. The boost sensor will make them open earlier or later depending on engine load. Something like 3600 - 4000 rpm depending on load.

You should pull the plugs on your injectors and check the voltage to each prong on the plugs. With the key in the ignition, you should get 12 volts to one prong on each plug, and nothing on the other one. You can also check the resistance across the 2 prongs on your injectors. For an 87 with low impedance injectors, I believe you should have 2 - 4 ohms. Someone please correct me if I'm wrong.

Also, have you checked to see if your engine is throwing any codes?

My car did a similar thing, but it only happened sometimes. Turns out my fuel pump strainer would get clogged with rust when the fuel tank would get low. I replaced the strainer, and it hasn't happened since.

HAILERS

Yes and no. Yes the secondaries will pulsate under 3500 if you pull the vac hose off the boost/pressure sensor. Problem here is he has a turbo car. He has to take the intake manifold off to get to the secondaries. Its not worth the trouble just to remove the injector plugs and check for 12v. The 12v is there anytime he turns the key to on. Not worth the time and trouble. Easier to access the small plug on the ECU to check for 12v. If 12v is there, the wiring to and from the injectors is good (we can make up a scenario where that isn't true, say one single strand of wire making the circuit, but unlikely) without pulling the intercooler and intake manifold. He can also check the resistance of the injectors by going to the solenoid resistor and ringing the wiring b/t the solenoid resistor and the small plug on the ECU. Yes, I should not have used the 3800 figure, wrong, should be 3500, but I still think its worth putting a meter on one of the secondary wires at the ECU and taking a look see at what is happening with the injector under a normal setting with the boost/pressure sensor connected. If the 12v does not drop considerably when he passes the 3500rpm, then the ECU is not doing its job. OH, REXMAN, if you have a voltage drop at (sorry again, should have said 3500 instead of 3800) 3500 rpm, THATS GOOD AND POSITIVE. That would mean the ECU has kicked in the secondaries and they are working. If you hit 3500 rpm under a load and the 12v, approx, just sits there, then the ECU is most likely not working and is the fault. Just takes a few minutes to check out, Have someone drive with you if your meter leads are not long enough. Let them monitor the meter. To make sure the injectors are not the high resistance ones i.e. 12ohms instead of the 2ohm ones that you should have, locate the solenoid resistor pack about a foot below your air filter. Its shiney aluminium with one large plug. Ohm out b/t there and the small ECU plug using the jpg I'm attaching. Just make sure the ECU plug is connected when driving the car and checking on the voltage drop. Car won't run without it being connected. Will have to stick the meter lead in the back of the plug to monitor. Piece of saftey wire or something similar to access the rear of the plug probably. Don't short it out to bare metal. And thanks for the correction about the 3800 rpms (should be 3500) and the part about the secondaries being active with the boost plug off. Just that the voltage drop under those conditions is very small compared to driving under full throttle.

HAILERS

If you get a good voltage drop, then the ECU is good and you need to look at the resistance of the injectors by ohming the wires from the PLUG on the solenoid resistor to the light green/red and light green/white wires at the ecu. Should be approx 2ohms. Might have to buy a long piece of wire to tie on one of your meter leads to reach the front of the car to get to the solenoid resistor. The clogged fuel strainer idea isn't too hard to check out. Lift the rug at the rear and you should see the top of the fuel pump. Oval in shape. Maybe ten approx screws attach it. If you round a screw head off just get a drill and drill the head off, then later remove the shank with pliers. I've had a fuel pump strainer that was clogged with a clear varnish over the mesh. The car would cut out driving around left corners if I was pushing it a bit. Starving. TAkes maybe thirty minutes to an hour to check it out. Less time each time you do it.

rexman13b

iTrader: (7)

I'll have to try that, but right now I'm in the process of rebuilding the engine, just decided to go ahead and do it, have a fresh start. Along the way I'm doing away with the BAC valve, EGR, cold start, OMP, gonna do pre-mix, AC, and all that emissions ****. So won't be able to tell what it's gonna do till I get finished, I'll let you know.

jacobcartmill

iTrader: (6)

MY 87 T2 would hit a brick wall at 3800 rpms, EVEN IF I TRIED TO RAISE IT SLOWLY. i didnt some experimenting and i found that my PRESSURE SENSOR WAS BAD. bad you tried replacing your pressure sensor with a different one? also when i replaced the pressure sensor, i realized that i didnt have a orifice(reducer pill) in the pressure sensor line that goes to the intake. try this my man.