Cold start injector will not work

89turborunner

Member
Authorized Seller
Joined
Dec 18, 2007
Messages
70
Location
oregon
Hello,

I have a 1989 7MGTE swapped into a 4runner. It has all the original equipment except EGR and it has a walbro fuel pump. COR and all other systems in place.

This rig was hard starting cold, so I started going through it. I rebuilt the CAS, checked all the grounds I could find (replaced nearly all of them, coil pack ground was faulty).

I found my CSI wasn't working. No fuel coming out. So I checked for fuel flow (I have plenty). I will install an AFPR soon so I will easily be able to check pressure later. I ininstalled a new fuel filter again just to be sure. Mine was only 2 years old.

I measured the timer switch on the t stat housing, resistance is good. I looked at the TSRM diagram and saw the timer got ground through the threads, so I thoroughly cleaned them, checked resistance to the thermostat housing (0.3 ohms) and then ran a brand new ground from the housing to chassis, #6 MTW.

I get 8.9 volts to one pin on the CSI harness plug while cranking. My battery is huge, fully charged, not old, and hooked up to an auto charger (15 amp). My battery is 100% not the issue here. I feel like this should be 12v.

I also have ground to the other pin on the CSI harness (with key to on position).

While cranking, I periodically get 8.9v between the two pins on the CSI harness, but only for half a second. Other than that, it shows 15 mV or less while cranking. This is zero to me, but its data so I'll report it. When I use the ground pin on the CSI harness and put the other lead to B+, i get 12.0+V while cranking. So the ground seems to be okay.

This engine runs and drives well once started. It takes seriously 5 to 10 minutes of screwing around with the throttle to start it. It is about 30 F here. I want this to work and I really dont want to hack in some switch or a permanent ground. Asking for your help everyone.
 

89turborunner

Member
Authorized Seller
Joined
Dec 18, 2007
Messages
70
Location
oregon
Oh and I also found in this (somewhat lengthy) diagnostic that my ECU ECT sensor was bad (infinite resistance) so I replaced it. I also put a new harness plug on for this sensor, mine was trashed. I also had a IACV that didn't pass the TSRM bench test, so I rebuilt it with a new (used) stepper motor from the same application. And I put in new iridium plugs and wires. This was all done prior to the CSI diagnosis.