I've been trying to track down the source of a strange idle problem and have decided it's a vacuum leak from the runners. So I ordered all the gaskets and they are slowly coming in. I figured if I'm going to have the top apart I might as well do some other things. I've also ordered some Bosch III fuel injectors. I know I have at least one leaking valve seal because of my puff of smoke on startup so I also ordered new seals. I'm considering 1.6 roller rockers too while I'm at it.

While I'm waiting for the parts I decided to give my engine a little physical. I did a compression test, and then I did a leak-down test. Here are the results:

LD% com cyl com LD%
----------------------
25% 165 8|7 160 26%
28% 170 6|5 165 25%
25% 170 4|3 165 30%
20% 177 2|1 166 25%

front

Compression doesn't look too bad for a motor with 186k on the clock. The leak-down percentage loss was pretty consistent except for cylinder 3 (30%) and cylinder 6 (28%). On both of those cylinders I could hear a hiss coming from the throttle body so I assume the intake valves aren't sealing completely. Probably due to buildup from the leaking oil seals. The air predominantly came out of the dipstick on all the cylinders and nothing came from the exhaust.

Once all the parts come in and I have the valve covers off is there anything I can do to clean any gunk off the valves without removing the heads?

Is there any point to putting 1.6 roller rockers on this engine?

Ron

I forgot to mention. I did the tests cold. I had the engine warm, but by the time I finished burning myself taking out the spark plugs it had cooled off.

 

Im willing to bet your engine heads need a rebuild.The numbers you posted arent bad for that mileage,but you might as well get it done right.

The valve guides wear out on aluminum heads big time and new seals will not fix the problem.

MY advice is to pull both heads,and have a machine shop rebuild them.

If it was my car,at that mileage,I would pull the whole thing and rebuild it all from there.Engine block and all.
Make it nice and strong again.

 

Do you know what size injector's your car uses?
BoschIII's are 24lb and I believe 88-89 are 22lb.

If you are going to invest in RR's, then rebuild the heads.
And put in a cam to take advantage of the 1.6 rr's.

I had a idle problem and it turned out my headgasket was leaking and I am right up there w/you in mileage.
One other thing, are you blowing smoke?

Wondering why you are thinking seals and not rings also.

 

The engine is not blowing smoke. There is just a puff of smoke on startup which seems to be an indicator of worn valve seals according to the research I've done on this forum.

Rebuild has been in the back of my mind for a while. I'm just not sure I'm ready to commit the time and money yet. I may push it a little while longer.

Thanks for you replies.

Ron

 

I have an 87 and put the Bosch III injectors in. The engine ran great. However, when it came time for the California smog it simply would not pass. So, I put my laptop on it and found that the ECM had maxed the fuel trim. It could not lean it out any more. I sent out the original injectors had them checked, cleaned and measured bringing them back to factory specification. I put them back in, took it back to the smog test station and it passed with flying colors. So, if one installs the Bosch III's they will run, but probably not in closed loop. With the short term and long term fuel trim maxed, I don't think the ECM will allow closed loop.
Currently, I have a set of the Bosch III setting on a shelf with a month of run time on them.

Just my thoughts.

Good Luck

Gary

 

Hmm, I hope mine behaves differently. They just arrived today and the paperwork says they are 22lbs just like the stock injectors. That'd be my luck to make things worse by trying to make it better. I'll make sure I hold on to the multechs just in case. Thanks for the heads up.