Hello, I recently bought an 89 f350 1 ton dump truck with a 5.8 l engine. It had a pretty healthy exhaust leak on the passenger side and I've been dreading tackling it for weeks now. Well today I finally got started on it and so far I've got 5 bolts out easy enough, one sheared the head off of course and 2 that haven't budged yet. While I was working on getting the bolts out I noticed that one of my secondary air tubes were cracked and had a nice hole in it which may have been my problem all along but I swear I checked everything first before I dove into the job. As much of a pain in the ass as this job has been in the driveway I can't imagine laying in the mud at a local pull a part to get the parts i need if I could even find them and I can't find the parts anywhere online. I figured somebody on the hamb may have an engine already pulled that may have the parts I'm looking for. I would be interested in the passenger side manifold along with the secondary air tubes if anybody has them. Thank you.
black flag? man, that was a long time ago. rock auto lists the manifold new, about $60, but they have plugs where the air tubes go in. and the air pipe assembly is out of stock
Yeah they started way before my day but still classic. Rock auto also lists the secondary air tubes but they are out of stock at the moment and I can't find them anywhere else. I'm happy with used if I can get my hands on them.
Thought about doing away with all of the emissions junk but I'm not sure if it would cause more problems or not. I've read mixed reviews online but the general consensus seems to be the computer doesn't like it very much. Thank you for the reply and please correct me if I am wrong.
There is a tube going to each exhaust port on the manifold and as far as I can tell only one is cracked so maybe plugging just the broken one wouldn't cause too much of an issue?
I would expect that just plugging a few of them would be fine. I know there were some Chevys made that only had a couple tubes, not one for every port, and they worked fine.
I will definitely try that if I can't come up with the parts in the next week of 2. Definitely still interested in the needed parts if anyone has them available though. Thank you.
Try Dorman. They have exhaust manifolds for almost anything. Do an eBay search, I bet you find one in 10 minutes.
Not sure about buying direct from dorman but the online parts stores I have checked are out of stock. The manifold itself is available everywhere but the secondary air tubes are not. There is one manifold on ebay with the air tubes attached but coming from Canada the shipping is more than the part.
Longish post, stick with it to the end to better understand the air injection system. Thermactor is the name of the Ford air injection system. Air injected at the heads/exhaust manifolds is used to initiate secondary combustion and aid in lighting off the catalyst. With feedback systems(O2 sensors) when cold the system will pump air at the manifolds/pre-cat to start the secondary combustion, when warmed up sufficiently the diverter valve will then inject fresh air down stream usually mid catalyst on 3 way catalyst, or in between the primary and secondary catalyst. In those systems the primary catalyst is a 2 way catalyst as found in 75-~'79 vehicles and the secondary catalyst is used for NOx emissions.s. This is why for the longest time many vehicles had two catalysts in line. Primary catalyst were 2 way, secondary catalyst was for NOx, later models now combine both into a single 3 way catalyst. NOx emissions were not tested til the 80's. Ford wasn't going to pay big money for 3way cats, so they retained using 2ways and then slapped the NOx catalyst on after. This is why, famously, Mustangs and other Ford vehicles have multiple catalysts. Mustang factory H-pipes have 4 catalysts rather than two, not because its an overreach of emissions compliance by the EPA/CARB/etc, its just simply Ford was not going to pay the premium for a 3 way catalyst. I'm sure there were packaging issues as well on existing platforms of the time. GM on the other hand, kinda boned themselves with 80's Fbods and packaging. Barely enough room for a single exhaust under the car, let alone multiple catalyst, so they have, famously, a single 3way catalyst. For packaging and price point issues this system was used throughout GM V8 vehicles of the 80s cars/trucks. Can justify 3way catalyst costs when you only use one and use a similar, if not same, catalyst on basically everything that has a V8. With feedback systems the fresh air cannot be injected before the O2 during closed loop operation as it will dilute the mixture which would indicate to the ECM that the engine is running lean when it is not. Diverter valve will then switch air injection to mid catalyst for NOx reduction or dump to atmosphere. If there is an airleak pre O2 sensor or the diverter valve is not working, there will be dilution which would cause a false lean signal to the ECM during closed loop operation. ECM will compensate and enrichen the mixture to 'fix' the problem but this will cause a rich running condition. Since the ECM *thinks* it is/has correct the problem it will usually not set a code unless there is a gross leak causing the ECM to stick to max enrichment which will eventually set a code for either O2 or mixture issue... maybe... ECM can only monitor O2 functionality, to a point, and if the diverter valve electrical is functioning within parameters. But this leaves the ECM mostly blind as it cannot monitor, actual, Thermactor function beyond this. It doesn't know when/where the air is being injected, only that it 'told' the diverter valve to 'do this' and if the system is whole, electrically, it assumes the system is functioning correctly. The physical state of the functionality of the system is an owner/operator/mechanic/technician issue. Failure modes of the Thermactor system are; Air leaks/general system integrity. Check valve leaks/failure. Diverter valve leaks/failure. Diverter valves tend to fail when the check valves fail. $5 part fails and takes out the $500 part. With pre OBD-II systems, one can usually remove/plug the physical air injection system and the vehicle will run fine as long as the diverter valve, or at least a similar resistive load, is still electrically connected to the ECM. These early systems are not directly monitored on where the air is being injected, only that the system is, electrically, whole. If you do not have emissions testing, the system can, for the most part, be abandoned if parts are unobtainable or the cost of replacement doesn't make financial sense. Just make sure the system is electrically complete to keep the ECM happy. If visual, no actual emissions testing, is required. Have everything hooked up, electrically complete, but just plug the system to prevent false air from entering the system which can cause running issues when a check valve or diverter valve is fried. If actual emissions testing is done, visual and gas testing, the upstream part of the system can be plugged to keep the engine running properly, but the downstream NOx will need to be kept functional to reduce NOx emissions. Basically you have to 'sleeper/Q-ship' the system so your average emissions tech doesn't start bitching about your thermactor manifold missing. Here in Calif, techs usually don't check actual functionality of the system, they look for it to be complete, no codes, and the emissions to be within parameters. A referee station will check for actual functionality of the system, but you gotta goof hard to be sent there.
I used '91 Mustang 5.0L stock headers on a Windsor powered F-250... I had to do hack job on the y pipe, but it worked....
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