kombatrok

Car is an early 86.

It was running well on Friday, just wanted to fix a vac leak on the throttle body and replace some wear parts. Had the intake all apart this weekend. After putting it all back together the car cranks but will not start...

I replaced the ISV, TPS, installed rebuilt 4 hole injectors from Roger and rewired the MAF connector.

The car has spark (checked with timing light off of both distributors) and the injectors fire (tested with noid light). The noid light & timing light look pretty weak, but I'm not sure what it looks like when everything is good. Please see the videos.

The fuel pump seems to come on when cranking and jumping the fuel pump relay makes no difference. I tried starting with the MAF plugged in and unplugged.

I have the battery off the car and charging now to make sure there is no way its a battery issue.







What else is there for me to check? It seems like it should have fuel and spark.

Mrmerlin

battery is low, charge the battery with a 6 amp charger for 4 hours,
clean the ground strap or replace it.

Did you swap in a new crank position sensor?
Did you check the MAF connectivity at the computer connectors?

From what you have now I would pull a few of the plugs to see if they are wet with fuel.
also check the fuel pump fuse if you find no fuel .
If no fuel then spray some ether into the intake and crank it see if it will run

kombatrok

The battery is charging now.

I did not change the CPS and the wiring to it appears to be in good shape.

The fuel pump was running, I verified that it ran with the relay jumped and I could hear it running for about a second after attempting to start the car

I'll take a meter to the computer connectors and check on the MAF.

Thanks

kombatrok

I have the LH connector pinout but I'm not sure what the correct readings on the MAF pins should be at the LH connector.

Mrmerlin

https://rennlist.com/forums/928-foru...MAF+adjustment

kombatrok

The MAF co is reading 312 ohms and the MAF ground is good as well.

I put a pressure gauge on the fuel rail and with the fuel pump running it reads 55 psi (87+ regulator for the s300 chipset) holds steady at 50 psi with pump off. Fuel pressure is good.

I got the engine to start using starting fluid, but it dies as soon as I stop spraying it in the intake. So I know spark is good.

It seems that despite the noid light showing an injector pulse and fuel pressure being good fuel is not getting to the cylinders... the injectors are from Roger, so I would assume that they are fine and it seems unlikely that they would all be bad.

What else can I check?

Mrmerlin

take a 9 volt battery and some jumper wires,
remove the injector connector plug,
jumper the injector to the 9 volt battery,
see if it makes any noise, it should click.
NOTE its possible that injectors can get stuck closed from having the cleaning fluid in them.
this test should be done to verify that injector will open

kombatrok

I will try that tomorrow and advise of the results.

Is the best way to check proper voltage to the injector harness just to put a meter on an injector plug and look for 12v while cranking? Or just 12v with the ignition on?

Also could a short at one of the injector plugs drop the voltage enough that they wouldn't open? If so can I check each plug to ensure there is no continuity between each side of the plug?

Thanks so much for the help so far.

Mrmerlin

best way to test injector wires is to use a noid light get it at FLAPS
shorted wires could kill the rest of the injectors

kombatrok

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kombatrok

I put a 9v battery to the new injectors, no click.

Old injectors cycle fine on the 9v so I swapped in the old injectors on the drivers side and the car starts immediately and runs on just the 4 cylinders. I guess the new injectors are just stuck/bad.

ROG100

Eddie - sorry for the trouble - I will have another set of injectors on the way to you tomorrow.

I have had instances where one or two injectors have had issues but a complete set makes me scratch my head.