ColoKevMan

86 22r 251K mi

Broken tc tensioner started whole thing - bent exhaust valves. Replaced timing chain, guides, tensioner and cover. Bought new head with new cam., remfg carb (had choke problems), remfg distb (advance now working fine), new coil, new cap, rotor, plugs and wires. Cleaned out (literally) cat conv. Have checked and re-checked vacumm hoses (can't find any problems here). Fuel in float bowl stays level when hit 3500rpm (see air bubbles though). Compression is low but acceptable (120,125,120,130 - not unexpected for bottom end with this many miles-so I'm told). Starts fine. Idles fine. Timing is spot on (had to tweak cam timing after initial instal to get to 0 TDC). Whether at idle or under load, once get to 3500 rpm, there is no longer any acceleration possible - it bogs down and seems to misfire (backfire in carb). Quite maddening! Any thoughts on what to check next?

justin_4runner

wrong jets in carb? have u checked the cat to see if its fried?

ColoKevMan

Think the jets are OK. Had same problem with the old carb ... trusting Carb Exch used correct jets in their remfg unit. I completely cleared out the cat (no emissions test here) ... it's hollow.

sb5walker

Since the minimum compression spec is 142 pounds, I would think the lack of power stems mainly from inadequate compression.

ColoKevMan

Has (plenty of) power/acceleration up until 3500rpm, then bogs down. This wasn't happening before replacing timing chain et al.

ColoKevMan

It was suggested that the cam timing be advanced equivalent of 1 tooth on cam gear (counter clockwise) ... did so but now cannot get to 0TDC. Distributor timing range is now 15 degrees to 45 degrees. Does that drastic of a change in distributor timing make sense from moving the cam the equivalnet of 1 tooth on gear?

OK - so I moved the distributor gear one tooth counter clockwise on the gear at the end of the cam. Corrected timing problem ... now can adjust distributor timing so it is 0TDC. Still loose accerlation once hit 3500 rpm although no longer have backfire in carb. Thoughts?

ColoKevMan

So, have moved the cam gear 2 teeth (counter-clockwise) on the chain meaning that the pin on the cam is also 2 teeth counter-clockwise when looking at it straight on. This is the only way the timing can be set and eliminate backfiring in carb. Starts fine, idles fine, sounds OK but no power with load after about 3500 rpm. This seems wrong ... that timing is achieved with pin on cam 2 teeth counter clock-wisw when it should be near 12 o'clock. Any input on what might be wrong?

toyotacharles

you describ to the letter same prob i had with my truck, found cam timing was 1 tooth retarded and vacc advance was not working either, once it found advance issue some of concern went away but still backfired through carb above 4000 whenever secondarys would open. fixed tchain issue and operating good. had same issue on 2 motors. could you have loose woodruf key on crank? is bottom chain gear on corectly(not backwards) pull off valve cover and look to see if chain scored on back side. could the timing mark on your crank pully still be corect, if not you could be alighning incorectly. did you get the corect timing chain set for the vehicle? there are 2 deck hights for this engine if you have the short deck and chain is for high deck , not certian if same chain is for both or not. is top gear on backward? wich side is mark on? can you see it. some basic stuff i know but never hurts to throw another look at it.

TNRabbit

I would suspect distributor advance not working properly. If that is OK, then your cam timing is off a tooth or TWO.

ColoKevMan

Both gears (cam and sprocket) are on correctly - no scoring on guides and can see both marks. Chain came in kit - compared it to another store bought one (96 link) and they were identical in length. Have remfg distributor - timing advances with increase in rpm - tells me dist is working. Move Cam timing another tooth or 2?? That would be 3 or 4 teeth counter clockwise from 12 o'clock for dimple on cam gear - that be OK?

toyotacharles

try to line up like this mine is lined up on other side of pin(pointed toward exhaust sid instead of intake as pics i find do) but mine is running great atm. My gear could be on backwards, now that's funny

ColoKevMan

Yeah ... that's the position I started at. In this position the closest to 0 TDC I could get was 8 degrees advanced and the carb would backfire like a big dog at 3500 rpm. I have moved the cam (gear marks) 2 teeth counter clock-wise (approx. 10 o'clock if looking straight on) and this eliminated backfire and can set timing at 0 TDC but no power above 3500 rpm.

Sportsmanphil

I would vote carb/fuel or fuel pump issue. Possible the pump isnt delivering enough fuel at 3500 rpm or higher?

toyotacharles

Ok so try this. Rotate cam one tooth clockwise(yes I know it will be too far but if im wright then I have same problem with my truck) make it line up on exhaust side instead of intake side. Or turn the cam gear around. Look closely at the offset of the pin to mark on that pic. If gear is turned around like I think it will have mark on both sides of gear for cam timing line up. Im going to go look at mine tomorrow. If you want I can take pictures and post em for you.

ColoKevMan

Brand new fuel pump. Float level (as seen via looking glass on front of carb) is good and stays the same ven as rpms increase. New (remfg) carb from Carb Exchange - haven't messed with it as I put it on and it started right up ... idling just fine.

Before moving cam gear counter clock-wise I moved it 1 tooth clockwise. When started it up it made a really bad noise - don't think piston hitting valve noise but like intake/firing/exhaust sequence way off. My cam gear does not have mark on other side.

Rust Capsule

So did the problem get solved? After replacing the head gasket and valve seals I am experiencing the same problem. She idles beautifully but around 3 K rpm there is no power. Did anything end up working for you?

ColoKevMan

No. Nothing has worked. Max speed on any kind of incline is 30mph.