351W won't rev above 2000rpm

[69RestoRod]

Working an 83 Bronco with a 96 351W(confirmed) that a shop halfass swapped into my buddy's truck. Took the 83 manifold and carb and slapped it on the 96 engine. He said it ran great for a few months, but the day he started his move back to AZ it crapped out. Had it towed to my place so we could look it over. I know it's not a Stang but the guys here know their stuff and I don't wanna be told to "Do a search" in a Bronco forum cause most forum search functions are worthless. I know cause I've been searching Bronco forums

Found and fixed a carb base gasket leak, an EGR leak and vacuum lines plugged with bolts and screws. Cleared out the emission hoses that weren't hooked up, considering gutting it all since it's not hooked up. Made a plate and blocked the EGR with a new gasket. Got the timing set so it's running with a steady 18 inches. Changed out the coil for a threaded post one as it had the ford odd clip style that was coming apart. Wanted to rule out a bad wiring connection, which it has a few. Found and repaired bad wire connections Installed a new starter which had to be shimmed, which I found odd. Then I saw the spacer plate had been damaged when the old engine threw a rod. The shop didn't replaced it just installed it bent to hell. The owner says it sounds and is running better than ever. But when you go to drive it it won't go above 2000 rpm, even in park when you rev it. I shifted manually and it doesn't seem to shift into third. Wouldn't it still rev to a higher rpm in 2nd or is the torque convertor holding it back.

Looking for answers or suggestions that I may be over looking. Been working on too many fuel injected manual trans front wheel drive cars recently.

 

[johnpro]

Throw a timing light on it, and see if the timing is advancing. Sounds to me like you're getting no advance, which means it's not going to rev.

 

[69RestoRod]

The vacuum advances the timing and the modulator on the distributor moves and holds with "Manually" applied vacuum, thanks for the tip John. The engine seems to rev up to at least three grand before it's put in gear. Problem I have is my dwell/rpm meters stops at 2K. The dash Tach holds off at 2200, but when I move the throttle by hand it's obviously reving higher than that. Currently checking into the gas pedal throttle linkage as it appears to be new and may have too much slack on the pedal. Also made sure it was in 2WH and not 4WL

The trans is also suspect to me. The truck is a Cali stolen/recovery with all the VINs pulled(found the original on the frame) and a replacement column in place of what should be a tilt with cruise control. Who ever installed it either used the wrong shifter cable or just did it wrong. None of the shifter dial markers on the dash line up to what gear you're actually in. Park and reverse can be accessed while the dial is still on P. I wonder if he had been driving with it partially engaged or in second rather than drive now and again. Fluid level is good and relatively clean with no burnt smell. I can get it to shift from first to second but no third, even when shifted manually. New vac line to the trans and no oil dripping from the modulator.

 

[Anonymous]

When I bought my 71 Bronco, the drive home was a slow one. It wouldn't rev very high either. Got it home looked at the throttle linkage and it had been adjusted so the previous owners wife (she was the DD) could not go over 50! Adjusted the linkage back to WFO and all was well.

 

[69RestoRod]

The linkage is fine just has a real short throw to WOT. I'm looking more into the 2bbl Motorcraft Variable Venturi 2700 and not hearing to many good things. Need to find a decent schematic of how they're supposed to be properly hooked up. If it's the problem it makes more sense to get a new 4v and intake than buy a $340 replacement. Looks like some work has been done to the carb as well, but that doesn't mean it was done correctly from everything else I've found.

 

[jims6t6]

Don't know if it applies to the Bronco but I thought that I had a problem with my 2001 Ranger which wouldn't rev above 2500. It has a rev limiter which will not allow it to rev above 2500 in Park or neutral.

 

[Starfury]

IIRC, those use one of those weirdo ignition control boxes mounted on a fender. I suppose it could be possible the box is fried. Some auto parts stores have module testers that can test them.

Just another idea.

 

[johnpro]

I'm looking more into the 2bbl Motorcraft Variable Venturi 2700 and not hearing to many good things.

I had one on my '84 Bronco, on top of a 351M. I absolutely hated that carb, but was afraid to replace it because of the strict California SMOG laws.

 

[69RestoRod]

The more I read into the EEC III systems and Motorcraft 7200 Variable Venturi carb the worse they sound. After their introduction they were only used in California and several other cars with the VV carb including GMs had a lot of problems. But since all the emissions stuff was falling apart and left to dangle on the new motor I don't mind removing it. This truck has an ignition system cobbled from two. Current solution is to get a EEC II ignition and non computer controlled carb off a similar year truck or bronco and install it. I'm willing to bet the carb is the main problem but since I can find little info on it just to make sure it's vac lines are plumbed correctly, swapping to the other style Ford used is a quick fix. The ignition is just going to be cheap insurance that we have one complete system. Will be a few days before he scrapes up the bread for parts but we'll see where this goes. It's nice to be working on a Ford V8 again, it's been a while.