dji1

I can do that. When I pull the check valve off, I will plug the line going to the intake.

94 Silverado 350 When I apply the brakes, the rpms drop. In park or neutral the drop is approx 150 rpms and in reverse or drive approx 250 rpms. When I release the brake, the rpms go back up to normal. I installed a new booster (rebuilt) last august 2025. Didn't have any problems until a couple of weeks ago. When I was working on the throttle body issues last month, I noticed some leaking around the booster vacuum line, so I replaced it. I have gone back and re-tightened the hose clamps and don't hear or see and leaks. I don't think the booster itself is leaking internally. The brake feels like normal and it stops ok. The pedal doesn't go to the floor, and I don't hear any hissing. When the truck is off, I still have pressure, so I guess the check valve is, ok? I do question the rubber check valve grommet. Maybe its leaking around it? The replacement hose was just a section of new hose. I plan to check it some more and test the check valve. When I rebuilt the throttle body, I did replace the idle air control valve with another one I had. It was almost new, so I don't think that is a problem. Any other ideas or test suggestions. Thanks

I was thinking about doing both. After I take the tbi apart I will clean and look things over. I am still undecided on redoing the fuel regulator. Normally I would just replace everything. Now I just want my truck back and running.

I hope so. I am surprised that the truck runs fairly decent with just 1 injector.

It looks like the injector is bad. I measured the resistance and it is less than .5 ohms. The good one is 15 ohms. I also found out that you can connect the injectors with either plug. Also, the individual injector connectors themselves are not polarity sensitive. So, I swapped the plugs and the passenger side would still not work. The driver side still worked. So, I can eliminate the ECM and wiring. I order a TBI gasket set and a new injector. Should be here in a day or 2. I think I may just remove the complete TBI and work on it off the vehicle. Thanks for all the help. I will let you know how it turns out.

I can't really check the working one. If I disconnect it the truck won't run. How do I check the ecm?

I started the truck and tested for the injector's ground pulse. I do get a dim light on the test light. Was the light supposed to flickering or stay on since the truck was running? I can use my voltmeter and see what the voltage is if that would help. Does this mean the injector has a problem? Is there a way to test an injector on the vehicle? Would measuring the resistance of an injector mean anything useful? Thanks

The passenger side injector is not working at all. It is getting 12 volts. I couldn't test to see if the ECM is sending a signal to the injector. No one around to help crank the truck today. I was going to buy a Noid light at AutoZone $5.99 but they don't stock it. They just advertise it online. I'm going to modify my test light and see if that will work. Didn't have a problem today seeing the injector (no) flow. The natural light was perfect. If the ecm is the problem, would it affect both injectors? Or if 1 injector is working then the other injector has a problem.

I am going to try the timing light suggestion. I purchased my timing light in the early 70's. It has a spring that you attach one end to the plug and the other end to the wire. It's not user for sure but it works so I have never upgraded. I also will try and set-up more lights so I can get a good look. The shadows under the carport were not good this afternoon. I can also move the truck to a better position if I need to. I will check the polarity of the connectors before I swap them. Thanks

It looks like the passenger side injector is not flowing much at idle. I think. It is hard for me to see for sure. I may just pull a plug on that side to see what it looks like. When I give it gas, I can see the flow on both ejectors. The driver side looks okay. Can I swap the connectors from 1 injector to the other side injector? There is a very small chance that when we soldered the new connectors on something went wrong. I took a video with the truck running. tbi.mov

Yea that is the 2 reasons I haven't bought one before. I am sure I would use it once and have no need for it again. The only reason I thought about it was that it was only about $20 and I have never tested fuel pressure before and I am not sure if 1 person could, do it? I bought a brake bleeder kit years ago that I forgot I had. Found it in the garage the other day. Brand new never used it. When I was checking it out to use all the nipple attachments broke in my hand. I may try the loner tool at the parts store. Never had in the past. I don't think the fuel pump is the problem this time. When I drive down the road the truck runs okay. I re-checked for vacuum leaks again last night and I don't hear any. I also checked the wiring to the o2. It looks excellent. I am going to re-check the injector patten in a few minutes to make sure. I didn't remove and clean the EGR valve last night. I replaced the gasket and cleaned it less than 10 years ago that is only less than 50k mile for me. I still may do it. Should I start a new thread for the idling problem? It is no longer a won't start issue. Thanks

I reset the kickdown cable back 1/4 turn. While I was driving around today, I finally got an error code 44 (lean exhaust) The truck was warmed up, and I was idling at a stop sign. I am going to re-check for vacuum leaks. I did replace the hose for the brake booster. I am going to check the wiring to the O2 sensor and remove and clean the EGR valve hopefully tonight. I have been thinking about buying a fuel tester at Harbor Freight just to eliminate pressure issues. Any comments? Thanks again.

No, the throttle body was not removed. Just replaced the electrical connectors. Ten years ago, when I replaced the tpi base gasket. I did adjust the kickdown cable then. I think someone told me on a 94 the kickdown cable was there but it did not control anything anymore. The sensors do all the tpi adjustments. I did notice that the kickdown cable was tight and had no slack in it like usual. Not sure why or if it even makes a difference on my 94? I did loosen it a 1/4 turn this morning.

I removed and cleaned the IAC. Disconnected the battery to reset. Same problem. I will drive it around tomorrow and see what happens. I didn't think there was too much carbon built up? The throttle top side plate is clean. When I was trying to figure out why it wouldn't fire, we sprayed quite a bit of throttle cleaner. Also, that is when we checked the injectors spray. All that seems fine. See attached photo's

The original problem was the injector wiring harness. OBD1, I will clean the IAC. I have had some issues with it over the years. Replaced the IAC and wiring 10 years ago.