Weird idol and no power when driving

[blairsj]

Have a 1990 TBI 5.7L v8. Starts up fine but after warmed up starts idling funny. Got a new distributor, ignition coil, EGR valve, EGR control solenoid, injector spray fine, PCV valve, throttle position sensor, map sensor, idle air control, oxygen sensor, and and did a throttle body repair kit.
After it’s warmed up, I noticed a ticking sound coming from the engine compartment on the passenger side not sure what that is.

Any help would be grateful. Thank you in advance.

 

[Chuckd84]

Have a 1990 TBI 5.7L v8. Starts up fine but after warmed up starts idling funny. Got a new distributor, ignition coil, EGR valve, EGR control solenoid, injector spray fine, PCV valve, throttle position sensor, map sensor, idle air control, oxygen sensor, and and did a throttle body repair kit.
After it’s warmed up, I noticed a ticking sound coming from the engine compartment on the passenger side not sure what that is.

Any help would be grateful. Thank you in advance.

Have you checked your fuel pressure or for any exhaust leaks upstream of the 02 sensors?

 

[blairsj]

Fuel pressure is good, and no exhaust above o2, just a pin hole at the y pipe

 

[gmbellew]

could be a big vac leak and the clicking sound is the stepper motor on the IAC bottoming out at 0 IAC counts and all the way closed.

is it idling high?

 

[blairsj]

Also no obd codes

 

[fast 99]

Were all the parts tossed at it in an attempt to fix the drivability issue? When did this first appear? Check vacuum, excessive engine noise may set off the knock sensor. What was the fuel pressure? They will not run properly at the low limit. Any exhaust leak pre-O2 can result in incorrect fuel trim.

Lack of check engine light doesn't surprise me at all. Those early systems were basic, that's why they are usually dependable.

 

[blairsj]

Not sure where the rpm are but it drops low like it wants to cut out then goes back up. I was thinking the clicking was the IAC so i put my ear right by it and it sounded like it was lower, also put my hand on it to see if I could feel it clicking but felt nothing.
It is in my plans to get a tech in the future

 

[blairsj]

Some parts needed changing others i just put on because it old. It started a few months ago, really notice it when I drive it up hills like it has no powers pedal to the floor and just barely gets up it. I haven’t checked the fuel pressure at the throttle body but in line after the filter and it was spec. Pressure.

 

[blairsj]

How would I go about checking vacuum? Looked at all the line and checked a few all seem to be in good order, no cracks that i can see.

 

[gmbellew]

All you need is an OBD1 blue tooth cable and thr ALDLDroid app on a phone or tablet to see what the computer seems from the sensors. Plus fuel trims, knock counts, etc. All in your looking around $100 or a little more.

With the losing power on hills comment, I am guessing large vacuum leak. Maybe even the intake manifold gasket.

 

[gmbellew]

How would I go about checking vacuum? Looked at all the line and checked a few all seem to be in good order, no cracks that i can see.

Put a vacuum gauge on the EGR solenoid port on the TBI. The solenoid shouldn't be trying to open at idle.

Use a mighty vac to make sure lines aren't leaking and are holding vacuum.

You can also measure voltage at the MAP sensor or use the aforementioned OBD1 cable and app to watch MAP values in real time.

 

[blairsj]

All you need is an OBD1 blue tooth cable and thr ALDLDroid app on a phone or tablet to see what the computer seems from the sensors. Plus fuel trims, knock counts, etc. All in your looking around $100 or a little more.

With the losing power on hills comment, I am guessing large vacuum leak. Maybe even the intake manifold gasket.

Okay I will look into the obd cable and app, thank you. I’m sure that would be a great tool to have in my arsenal

 

[blairsj]

Put a vacuum gauge on the EGR solenoid port on the TBI. The solenoid shouldn't be trying to open at idle.

Use a mighty vac to make sure lines aren't leaking and are holding vacuum.

You can also measure voltage at the MAP sensor or use the aforementioned OBD1 cable and app to watch MAP values in real time.

The egr port you are talking about is the one in the middle of the throttle body?

 

[Camar068]

@Billy where's he at when you need 'em.

 

[gmbellew]

The egr port you are talking about is the one in the middle of the throttle body?

I think it's the middle one. check the sticker on the core support to be sure

you can also spray carb cleaner around in suspected leak locations and see if the idle changes. if it does, you found your leak.