Norton Posted March 21, 2023 Share Posted March 21, 2023 Hey fellas I have an 89 2.5. On cold starts I have to stay on the gas to keep it from stalling and same goes for the first 10ish minutes of driving. Once it warms up, it idles and drives beautifully. Here’s what I’ve done so far: Bought and installed new ISA, and it’s working like it should and engages the throttle arm just fine. Fixed a couple vacuum leaks around the TB. Cleaned throttle body. Checked that the EGR is working as it should and isn’t sticking. None of this really changed anything and it still runs really bad on startup. I’m thinking about replacing the ECU next but wanted to see if anyone has any other ideas? Cheers thanks Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 21, 2023 Share Posted March 21, 2023 Has the ISA been adjusted properly though? Fully extended ISA unplugged should be about 3500 rpm + or - 200. Link to comment Share on other sites More sharing options...
Norton Posted March 22, 2023 Author Share Posted March 22, 2023 I don’t have a tach, just dummy lights so it’s hard to tell. By ear it sounds like it barely loping along at like 300-500 when cold before stalling. Once it to starts idling normally it feels like about 1500. Do you mean physically backing out the screw with a wrench? Or is there another adjustment? Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 22, 2023 Share Posted March 22, 2023 Physically backing out the screw on the ISA is the only adjustment. You can either get a aftermarket tach and put it in the pins of the diagnostic plugs or get a full cluster orrrrr an REM from nickintimes. Those three will give you RPM. Idle for AC 2.5Ls with AC on should be 1k and off should be 900. No AC should be 750 unless you have the harness that bumps up the idle to 1k like you have AC. Link to comment Share on other sites More sharing options...
cruiser54 Posted March 23, 2023 Share Posted March 23, 2023 Make sure the intake manifold bolts aren't loose. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 23, 2023 Share Posted March 23, 2023 Yeah I second the manifold bolts too speaking from a recent experience. Link to comment Share on other sites More sharing options...
TheDirtyJeep401 Posted March 26, 2023 Share Posted March 26, 2023 How long has it been since ignition components have changed and or been inspected? Plugs, rotor, cap and wires? Even the coils condition. I recently had the same issue. And found that most of it was caused by old plugs and a weak coil. Would not run at all in the cold till it got warmed up. Replaced all the worn out components. Actually idles when it’s below freezing now. Link to comment Share on other sites More sharing options...
Norton Posted March 27, 2023 Author Share Posted March 27, 2023 By intake manifold bolts do y’all mean the bolts that hold the manifold to the block? Are there any bolts on the manifold itself I should check? Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 28, 2023 Share Posted March 28, 2023 Yes the ones that mount the manifold to the block are common issues if they haven’t been torqued to specs. Link to comment Share on other sites More sharing options...
cruiser54 Posted March 28, 2023 Share Posted March 28, 2023 Intake manifold to head. The factory torque spec was too low. Link to comment Share on other sites More sharing options...
Norton Posted March 28, 2023 Author Share Posted March 28, 2023 Tried this and the bolts were pretty tight. Tightened them some more and the problem is more or less the same. I also snapped this little hose going from the throttle body to the valve cover on accident. Felt like it was sending air to the TB. Weirdly enough it made the idle a little better. Starting to get stumped. Link to comment Share on other sites More sharing options...
Norton Posted March 28, 2023 Author Share Posted March 28, 2023 Heard something about disconnecting and touching the battery connectors together for 30 secs to reset the ECU. Anyone ever done this? Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 28, 2023 Share Posted March 28, 2023 31 minutes ago, Norton said: Tried this and the bolts were pretty tight. Tightened them some more and the problem is more or less the same. I also snapped this little hose going from the throttle body to the valve cover on accident. Felt like it was sending air to the TB. Weirdly enough it made the idle a little better. Starting to get stumped. Yes but when stuff is properly adjusted, the idle will shoot up to 1200 rpm which is a good balanced idle but too much for the 2.5L. 28 minutes ago, Norton said: Heard something about disconnecting and touching the battery connectors together for 30 secs to reset the ECU. Anyone ever done this? won't do anything. The ECU operates from the EEPROM and doesnt store any codes. Have you tried adjusting the ISA yet? Link to comment Share on other sites More sharing options...
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