No fuel on starting

1986 2.5L throttle body injection Jeep Cherokee. The Jeep has had trouble starting in the mornings. Now it doesn't want to start at all. I have to crank it multiple times before it will even consider starting. I found that fuel isn't being sprayed during cranking The butterfly in the throttle body is completely dry. If I spray some carb cleaner in the throttle body, it will start right away. Once it's started, it runs fine. It does have trouble starting at other times through out the day. I checked the fuel pressure and it's reading fine (15-17 psi). I am thinking that the injector is bad, but I want to know for sure before I speed the money for it. Any ideas?

Anyone?

Rather than spend the $$$ on a new TBI, run a can of BG44K through the gas. Most likely it is just sticking.

I ran some fuel cleaner twice through the fuel system with no improvement. I was thinking that the injector was bad and not the throttle body.

Most times on the GM TB it's the regulator. Occasionally the wiring to the spray head.

IF it runs OK after it has started, I would think the injector and fuel system is OK. I would look for something that is not getting reset or set properly for the start up, or something that operates diferently at start up versus running.

I have an 87 Renix MPI manual (so it may not apply to yours) that lists an idle speed regulator on the 4 banger that could cause your problem. Since yours is a throttle body injected (86) and not Multi Port Fuel injected, I just don't know, but this might give you a starting point, or it might be the same part and operation for both years.

You might also check for a fuel pump ballast resistor and see if the start mode on it has burned out. It was not used on all years, but I show it on the 87, 4 banger so it might be on yours too. It had two resistors, one for starting and one for running, so if yours has a ballast resistor it is a likely suspect as well.

Is it have any other problems at all?

8Mud said:

Most times on the GM TB it's the regulator. Occasionally the wiring to the spray head.

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X2, if your describing the idle speed regulator. It sounds like the perfect suspect. I just wasn't sure it was used on the throttle body injected 86 model.

I have an Idle Speed Actuator (ISA) on the throttle body. 86 and 87 look like they are the same according to the pictures on Kragen.com. I don't see any resistors for said motor (actuator) in the engine bay nor in the wiring diagrams I have. I don't have any other symptoms. I think the injector is pulsing, but I need to actually check it when it's starting.

Schris1 said:

I have an Idle Speed Actuator (ISA) on the throttle body. 86 and 87 look like they are the same according to the pictures on Kragen.com. I don't see any resistors for said motor (actuator) in the engine bay nor in the wiring diagrams I have. I don't have any other symptoms. I think the injector is pulsing, but I need to actually check it when it's starting.

Click to expand...

The resistor is in the fuel pump power feed, if it is there. It controls the voltage to the fuel pump, which affects the pressure between start and run modes.

It is actually a single white ceramic block, 2 resistors inside, one for start up and one for run. If the start resistor burns out it causes the no fuel at start up problem!