No Top End Power, 1.8 L-Jet Options

[motorvated]

I'm not expecting much from a 1.8 but seems like it is lacking power under load at higher rpm. Top speed is about 80 mph, and not enough power to get it into 5th gear. Engine is tuned, distributor is cleaned, timed and has full advance, point gap is to spec, valves adjusted, new air cleaner, fuel filter, plugs, points, condenser, coil, wires, cap, and fuel pump. New fuel cell, so no tank sock issues. Throttle is opening all the way, and fuel pressure is to spec under load. Injectors cleaned with good spray pattern, cold start valve not leaking. New vacuum lines. EGR, decel valve, and crankcase breather all still hooked up to intake snorkel. Tried two different AFM's, and although one seems a little stronger, it's still weak at the top end. Even went through the AFM static and dynamic mixture adjustment procedure on one of them to set it at " just lean". Richening it doesn't help. The only thing I haven't yet checked is compression, but engine idles smoothly, burns no significant oil, and pulls cleanly to about 4,500 rpm. Don't yet have an AFR to confirm mixture, but planning on getting one soon.

Running out of ideas, anyone have any suggestions? Should I disconnect the EGR, decel, and route the crankcase breather to a catch bottle to rule these things out as potential contributors to the problem? Obviously, I need to do a compression check. I'm running the cat at elevations ranging from 4,500-7,500 feet above sea level, so that will have so effect on performance, but I expect more than I'm currently getting.

[timothy_nd28]

Emergency brake stuck on?

[motorvated]

Emergency brake stuck on?

All new brakes including parking brake cables. Car rolls freely.

[injunmort]

i know you said distributor was serviced, but sounds like it is not advancing fully or the timing is off. also check dwell of points.

[Cracker]

Did it ever have top end power? Have you checked compression? Low compression - low revs.

T

[timothy_nd28]

Adjusting the airflow meter should really only be done with the proper test equipment. Since it's been modified, we don't know what the AF ratio is anymore. See if you can borrow those portable air fuel meters, the one that attaches to the tail pipe, and drive the car. Record the data at all speeds.

[motorvated]

Car barely ran when I bought it. 3,000+ rpm idle, vacuum leaks, bad dual relay and Jerry rigged fuel pump. Found gas in the oil. Couldn't have been driven or even run very long in that condition. I only adjusted one of the two AFM's, the other has never been opened up and it's a little better, but still not strong getting to redline. There's a great thread on how to adjust them based on how the engine responds to changes in input. I know for sure that I'm getting full advance from the distributor, as I'm using a timing light with the degrees advance capability. Points are gapped correctly, so dwell has to be good. Compression check and AFR check are next. Can high rpm performance be improved a little by tightening the valve lash just a little, say from 0.008 to 0.007, and letting it breathe a little better, but not too tight to burn valves?

[Dave_Darling]

Since the spec on the 1.8 is 0.006" for all valves, you might try that and see what happens. I doubt it will improve much, but you never know.

--DD

[Valy]

Check for vacuum leaks, again.
Check ignition timing and dwell.
Check fuel pressures at high RPM.

[toolguy]

As said before, do a compression check before anything else.

[porschetub]

You found fuel in the oil ....not good,wonder how long it had been run like that,its called bore washing and plays havoc with the piston ring lands over time resulting in piston wear and compression loss in extreme cases the rings usually break.

As mentioned a compression test is in order then you will really know,I would snug up those valve clearances also a DD mentioned,good luck.

[injunmort]

not to be a dick, but here goes.... if you are sure you have no vac leaks ( lean condition) your timing is off. plain and simple. not enough advance, not enough dwell = not enough fuel under the load. what is your dist? what mark are you timing it to? are you using a light or static timing?i know you calibrated this before. do it agin.