89 Bronco, 302, EEC IV, E4OD. Last year it was loosing a lot of fluids, so I ended up taking the motor apart and rebuilding it. (First time-er, Thank you FTEs that helped) I finally got back to that project (because I need to use the truck) and got it running. That said, I still have a long list of things to address with the truck. One of the bigger problems is the rot. I don’t think that I will win that battle, so I am trying to keep the rest as cheap as possible - maybe get another year out of it.

It feels very sluggish, like I have a hefty trailer attached, and seems to be running hotter than it should. The last run code only read 33 – EGR not opining. Could that be causing the lack of power or should I be looking else ware. Any suggestions would be greatly appreciated.

 

You need to check your timing. It should be set at 10 degrees with the spout out. On an '89 follow the harness coming off the ICM and you'll find a grey connector with a jumper in it. Remove that jumper and check the timing. It sounds like it's running retarded. This will make it run hot and have a lack of power. It's also possible that a mouse has built a nest in your muffler. This can easily be tested by removing the muffler (either sliding it off if possible or cutting it off), and then test driving it.

 

i would suspect the timing, or a clogged cat converter. I also didnt think the e4od was in the bronco in that year, is the OD Button on the dash?

when the motor was rebuilt did you upgrade the cam by chance?

 

the Haynes said the timing was usualy at TDC. I dont have the sitcker to tell me other wise. So that is where i have it. is that 10 deg BTDC? also all I have is a needle not a scale, is there any easy way to determine how far from the needle 10 deg is?

the mufler is not that old, but the cat is origional. I was wondering if i should be suspicious of it. is there any other way to check the cat other than crusing the neighborhood with no pipes?

I might be wrong about the E4OD. It has no OD button. unfortunatly the cam was not an up grade. I was just a basic rebuild kit. I would love to actually fix this truck up right, but the rust is a major issue. I'm kinda going for pass inspection cheap at this point.

 

was the rebuild kit for your year truck motor. if it was for an older 302 or for a mustang for instance the cam may not be compatible with the computer

take some chalk and rub it on your balancer, so there is no timing pointer there? btdc with spout connector removed would be correct and maybe the cause so lets start there and worry about the cat after you get this part taken care of

 

the kit was a Sealed Power master rebuild kit. it was suposed to be for that year bronco, but i did have a real pain of a time getting the right rings. apparently I have the mustang metric pistons. Ill try the timing shortly and report back.

 

In '89 ALL truck and van engines were 10 dbtdc.... You would set the timing at TDC for the initial start then adjust it to the timing spec of 10 dbtdc, you may even get away with as much as twelve.

 

Much better. Temp seem better. Power is also alot better, but not leaving any patches of my not so meaty tires anywhere. I put some mufler cement on a thin crack where the two pipes meet the cat. it was quiet at first start, but blew out the patch pretty quickly. should I be suspicous of that 17 year old cat?

 

yeah- when convertors get old they can restrict flow. Get a new one and scrap the old one. I dont know about where you are but I've been getting $40 for scrap convertors and a new one is a little over $100

 

look into the bassani Y pipe with hi flow cats. its really a great setup and flows awesome. the stock Y is very restrictive not to mention a 17yr old cat.

 

I would deffinatly check timing, cuase i did a rebuild on my 89 and the times was off by 4 degrees and it felt like i had a battleship anchor tied to it

 

I recently rebuilt my 1987 bronc with a 302 ! Going through the motor I could see it definately needed it the valves were shot play in the crank all the stuff you dont want to see. I bored it 40 over put a three way valve seet grind on the heads ported and polished the heads and port matched the upper and lower intake . i even did some light porting on the throttle body i say light now because i port matched one and my speed density computer hated it. I was was expecting big gaines and it still ran like a dog!!!!!!!!!!!!what the &$%^. I did the same thing went through the timing started sweating my cam since i did have the block rebuilt and new stock cam installed,bored 40 over. I then looked to the exhaust my old exhaust manifols were both cracked , since replaced . Ive heard a plugged catalytic or catalytics like on mine can cause cracks or leaks in the exh manifolds due to excess heat and or pressure. this is a common problem on these trucks and broncos hhhmmmmmm. Cut off my cats and sure as hell they were both clogged Im lucky enough to live in a place where we have no emissions.I dueled out my exhaust ,oh a little trick i did to keep my stock oxygen sensor was i got an identicle right side 302 exhaust manifold off a truck. Except it had a port for an oxygen sensor it plugged right in sweet and no codes! without those cats this thing goes like hell for bein a 302 in a full size bronco . And it was pretty much the same power difference with the cats off before i put on the duel exhaust. Yeah it was a lot louder LOL. OPEN ehaust. The difference was night and day in my power!!!! With all those mods extensive porting and duel exhaust my speed density computer hasnt even thrown a code 111 baby . My transmission doesnt even hunt around for gears on the highway anymore it gave me power all over ! The thing is with all the mods i had made i couldnt even really see how much horse power i had gained until i got those damned cats off looking in at them one side looked fine the front side facing the motor was all melted to hell ! These cats are years old and have bein abused by people and who knows how many people unless youre the original owner! If you know youre motors tuned right definately hit those cats. Im not a hater of catalytic converters and i know they do good things but in my case they were the demon that was smiling at me in the dark. I have found that 40 over bore and extensive porting havent pissed off my speed density computer at all this thing halls *** for what it is relatively stock except the exhaust . hopefully this helps someone who has speed density at least it my case it works daily. im also running a computer out of a 1989 bronco with speed density and it has given me smoother shifts and easier start no kiddin . The computers i swapped around are all pinned the same but the computer out of the 89 is the 1 i kept $10.00 bucks at my local junk yard it like i mentioned smoother shifts. Sorry for the long post guys.

 

They do check emissions here, and I do beleve in the global warming problems, so I guess I'm looking at a complete exhaust system. Its a big comitment for a truck that has such massive rust problems. Anyone know a way to turn rotten frames back to solid steel? Maybe I'll start a new thread about the rust over in the big bronco forum. Thanks for the engine help.

 

I rebuilt my son's 89 302 over a year ago--even splurged and put one of the comp cams speed density cams in it. It ran like a dog too after I put it all together and set the base timing at 10 degrees. I gradually started moving the timing up and it gets better every time. Now it is at 18 degrees BTDC. Still no sign of spark knock or detonation pinging, and its running more like I thought it should--I'm very concerned about having the base timing that high though! I'm not sure what's going on--maybe my cats are plugged up too? If so, would advancing the timing mask the effects of plugged cats?

 

I know a couple of symptoms that i had when my cats were clogged was a very slow and limited rev! My bronc wouldnt rev over 4000RPM. And you could tell that it was being helled back power wise. Also on the freeway it would not hold cruise control on a hill or when the wind was blowing hard for that matter. After the cats were off it would actualy stay in cruise with minimal effort at 75 MPH and i could still give it gas without it kicking down and it now revs much quicker and higher in the RPM s! 18 degrees of timing is quite a bit its possible that if youre rev is limited ( no top end RPMS) it might not knock since it would basicaly be retarded like mine was! Premature no giddy up LoL. For me it was like my motor couldnt advance fully! I think its possible you could be masking clogged cats with advanced timing , and if that were the case if you took off youre cats and left the timing at 18 degrees she just might start pingin ! If youre cats are plugged like mine were youre motor will be retarded and incapable of reaching full advancement! Im no pro but i walked down the same street youre walkin right now and those damned cats were definately my problem. I would definately give them a good look if possible! Big truck or not these 5.0s were desighned to rev smoothly and quickly and after i got the clogged cats taken care of it was like i bolted on a spare set of nuts! Hope you get it figured!