Replaced Starter Now Engine Idles Rough

[Ronstang66]

I am really not sure what is happening here. I had to repair my starter and everything has gone south due to this what should be a simple problem. The engine now idles rough with a definite small popping in the exhaust. The check engine light stays on constantly and the only code registered is 52 which is the No. 1 knock sensor signal.

Over half of the injector wire plugs fell apart during disassembly. I had to order a complete new set and solder them into place. I used self sealing heat shrink and all the connections were good. I can't see how I could have gotten any wired in backwards as I did them one at a time and was careful to keep them oriented the same way. Is there a polarity issue here? Could this possibly be my problem.

I really don't know what to do here. I need this car fixed ASAP but cannot locate the problem.

Could a vacuum leak make it run this rough?

What side is the No. 1 knock sensor on, the passenger or driver's side?

I could really use some guidance as I am really frustrated and have been without this car for 3 months now due to a starter that simply had burnt contacts. This is getting ridiculous.

Thanks in advance, Ron

[python]

its on the number 1 bank...find number 1 plug and thats the bank its located on but guess what...the knock sensors are located right where your starter is, that job u just did...plan on doing it again, this time replace both knock sensors and go to the dealer and get the connectors to the knock sensors...pm me with any questions u might have

[Ronstang66]

I don't mind doing the job over if it fixes the problem but can you explain how and why the knock sensor could be causing a rough idle?

[IanRShearer]

I don't mind doing the job over if it fixes the problem but can you explain how and why the knock sensor could be causing a rough idle?

"Knocking" is when the spark is too far advanced and the burning fuel tries to push the piston back the way it came. It produces a knocking noise.

The knock sensors detect this and the car ECU can ammend the spark timing. Presumably your car is having to guess the exact timing for one bank.

To be honest, I wouldn't have expected it to make that big a difference to tickover, but I don't have the experience to know

[steve2006]

If you look at the picture below it shows the position of the knock sensors ( one is labelled 2R and I think the other across and forward is 1L) as you can see it is very easy to damage them or the wiring when removing the starter motor.

I did the same job this weekend fortunately it all went without problems apart from breaking a fixing clip on one of the injector plugs.

BTW did you remove the inlet manifold complete with the injectors or did you separate the injectors if you did separate you will need to replace the injector O rings or you may have leaks in the induction system which may be causing the problem you now have with rough running.

[Ronstang66]

I cleared the codes today and now there are none. I also listened to the engine along the tops of the valve covers very carefully with a stethoscope and everything sounds normal and consistent from cylinder to cylinder.

I guess I either have a vacuum leak, miswired one of the injectors or one is sticking after sitting for 2 months, or I could have a damaged spark plug wire that is just not visibly arcing.

Steve...I did not replace the o-rings so that could be the problem but there are no fuel leaks. I could not get the lower intake off without removing the fuel rails as some of the bolt to the lower manifold were blocked by them.

[python]

code 52 will be back if the sensor is in fact bad..none of which u stated in ur last post will cause code 52...sorry

[curiousB]

Here's a couple ways to search for a vacumn leak(s). Its a bit dangerous so be careful. I think propahe method might be cleanest and safest.

Method I How Do I Find if I have a leak?

The best method is to go to the Auto Parts store and get a can of Starting Fluid. This is basically Ether. This is a very volatile substance that is easily sucked into a leak and causes a dramatic change in engine running condition.

With the car at idle spray carefully around the base of the carb or throttle body, at the area where the manifold meets the head, around vacuum hoses and any connections either below the carb base or after the Mass Air or Air Flow Meters. Any noticeable change in idle speed or quality will indicate a vacuum leak

Methond II ENGINE VACUUM LEAK DETECTION

Okay, now that we have covered what a vacuum leaks do, how do you find components that leak vacuum? One way is to visually inspect all the vacuum hoses and connections. Look for disconnected, loose or cracked hoses, broken fittings, etc. Hey, you might get lucky and find the problem in a few minutes, or you might waste half the day trying to find the mysterious leak. Vacuum leaks are often the elusive needle in a haystack. And if it is not a hose leaking vacuum but something else such as a gasket, worn throttle shaft, injector O-rings, etc., you may never find it using this technique.

A faster technique for finding intake manifold vacuum leaks is to get a bottle of propane and attach a length of rubber hose to the gas valve. Open the valve so you have a steady flow of gas. Then hold the hose near suspected leak points while the engine is idling. If there is a leak, propane will be siphoned in through the leak. The resulting "correction" in the engine's air/fuel ratio should cause a noticeable change in idle speed and/or smoothness (Note: on engines with computerized idle speed control, disconnect the idle speed control motor first).

Aerosol carburetor cleaner can also be used the same way. CAUTION: Solvent is extremely flammable, so do not smoke or use it if there are any sparks in the vicinity (arcing plug wires, for example). Spray the solvent on suspected leak points while the engine is idling. If there is a leak, the solvent will be drawn into the engine and have the same effect as the propane. The idle speed will suddenly change and smooth out.

[steve2006]

Please don't be offended but did you use new gaskets on the plenum chamber, intake manifold etc?

Also connection # 2 on the injectors should be connected to the orange wire.

[Ronstang66]

Please don't be offended but did you use new gaskets on the plenum chamber, intake manifold etc?

Also connection # 2 on the injectors should be connected to the orange wire.

You can't offend me. I have been working on cars for 30 years and learned a long time ago to ask questions when you get stumped and to be prepared to find out you did something wrong. I am not sure what you mean by "connection #2" on the injectors. If you can clarify that I will double check the wiring on all the injector plugs just to make sure. I was careful to only cut one plug off at a time and keep the connectors clocked properly but that doesn't mean I didn't mess one or two up. It happens. I did use new gaskets also, and since I now have the upper intake off once again I will replace them again.

I did find the problem. You were correct earlier. The injector seals are bad and so are the coatings on the bottom of the injector pintle caps so just putting new seals on is not going to solve the problem. I have to call a local injector rebuilder in the morning to see if they can replace the caps for me. They are never going to seal any other way.

Thanks

[90LS400Lexus]

Kinda o/t, but when I emailed that photo of the starter location to my dad he said for me to sell my car before anything like that happened that I could not afford to repair. :) I had intended on giving this car to my mother, but I think he dont even want her to have it, because of the complexity of it, but thats understandable I guess. I may give her my other car, sell the LS and buy me a truck.

Hope you get yours fixed.

[python]

those caps that are on the bottom of the injectors do not seal anything, in fact u can use injectors out of a sc 400 which are a little different design at the bottom and dont even have those caps on them, they put out a little more fuel but ur ecm will adjust for that in a few days

i thought this problem was fixed? did ur cel come back on? code 52? if so then like i told u earlier u r going to have to replace the kock sensors as well as the connectors

[Ronstang66]

those caps that are on the bottom of the injectors do not seal anything, in fact u can use injectors out of a sc 400 which are a little different design at the bottom and dont even have those caps on them, they put out a little more fuel but ur ecm will adjust for that in a few days

i thought this problem was fixed? did ur cel come back on? code 52? if so then like i told u earlier u r going to have to replace the kock sensors as well as the connectors

The seals that I got were too big and fit loosely on the injectors without the pintle caps. I found a place in town that had the caps and the guy gave them to me. This issue is resolved but now I am tackling the timing belt, water pump, and valve cover gaskets since the car is so far apart already.

[steve2006]

those caps that are on the bottom of the injectors do not seal anything, in fact u can use injectors out of a sc 400 which are a little different design at the bottom and dont even have those caps on them, they put out a little more fuel but ur ecm will adjust for that in a few days

i thought this problem was fixed? did ur cel come back on? code 52? if so then like i told u earlier u r going to have to replace the kock sensors as well as the connectors

The seals that I got were too big and fit loosely on the injectors without the pintle caps. I found a place in town that had the caps and the guy gave them to me. This issue is resolved but now I am tackling the timing belt, water pump, and valve cover gaskets since the car is so far apart already.

You are a braver man than me, I do most jobs myself but when it came to the timing belt it went to a local indie.

[curiousB]

This issue is resolved but now I am tackling the timing belt, water pump, and valve cover gaskets since the car is so far apart already.

Let us know how that goes. I have that same repair coming up in 10-12 months and am educating myself (and trying to build up the courage) to do it myself. Would be interested how it goes. Particulary intereted how you get the bolt off crankshaft and pull harmonic balancer. Sounds like that can be a tricky part to the repair.