ideas on loss of power in 78 fi bus?

So last I drove the bus to SC... My bus would run great on flat land but I couldn't pull any hill unless I was in 2nd... These hills weren't that big... nothing Asheville style like I have done so many times before... Fuel economy was pretty good. It is a 78 with stock fuel injection. I honestly cannot remember what I was getting, probably 17-18 mpg+. This is about what I have always gotten in this bus, never more than 20 mpg. I would have to do some research to see if I ever even got that. I know it is supposed to get more... but hey... that was in 1978.

So, I had not changed the plugs in 5 years, 30k miles. I use to change my plugs every 15k miles, but they always seemed too new and a lot of spark plugs say they are good for 100k miles. Well, these didn't seem to have any wear, gaps were the same as they should be... .032

3 of the plugs were a whitish greyish color residue on the plugs... I am unsure if the color is more of a normal color or if it is a sign of running lean... I've looked at more color charts than I care to list... I always thought it was a lean color, but the interwebs seem to suggest otherwise. The last plug, I think it was #4? fairly certain... it was black, not wet, just definitely black.

I replaced the Bosch Super plugs today with Bosch super plus plugs (they are some weird looking plugs!) and I *think* I have power again. I drove up some small hills and I was gaining speed rather than losing it... then again these werent very big hills.

My injectors are also original to the bus... so they are 32 years old... I have never had them tested... I have 4 new ones in a box to put on, but not sure that I need to just yet... I am in a time crunch to go camping friday morning and dont want to get too deep in... I have never replaced injectors on a bus with the engine in. Is it difficult? Anyone have procedures online? If it doesn't take too much time I am all for it... is there anything else? seals and whatnot that I will need to replace when I do it?

Did replacing the spark plugs fix my issue you think? How often should I replace them and how can I tell they are bad? these really didn't "look" bad, just dirty.

Ideas?

its pretty easy to remove/replace the injectors, if you have new injectors and new seals i say go for it. you prob should replace all those fuel lines when your in there as well.

its been so long since i replaced them that i forgot... not to mention that the engine was out of the bus when i did it. I also hate throwing parts at things... but i guess it can't hurt to replace the injectors. I justify it to myself by saying i am replacing the lines! Do you think that is it though? or should I be looking elsewhere? I plan on doing a fuel pressure test tomorrow... i need a good compression test kit though. any idea where i can get the right size screw in type?

I agree with you about not replacing things just for the sake of replacing them. I would let someone check the injectors for proper spray patterns. The sooty black plug can mean many things. Bad plug wire, cap, coil. Or, maybe you have a problem with a valve. Have you checked that? Then there are the Bosch plugs. Some of them just arent what they used to be. They are certainly not 100,000 mile plugs, but a good 20-25. How is the bus running otherwise? Any skipping? Overheating?

if you haven't already, i'd just go ahead and replace the fuel filter as well. the black sooty plug might also be an injector stuck open. won't know for sure untill you get them tested, or just replace them. if they are origional to the bus, then i'd prolly just replace them anyway.

my filters are clean... yes i have two... i thought i had an issue last fall after i replaced the tank so i put a clear one in line...its still clear and comes before the white one... last white one i cut open and it was clean even without the secondary filter.

My injectors are original to the bus so far as i know... I have receipts for everything else so would assume those would be in there if they had been replaced. is there anyone around here who tests/cleans/ rebuilds them (do you really rebuild injectors?). It would be nice to know if they are in good working order or not... 32 years is a long time... especially with all the down time this bus has had. That is probably why I have never gotten the fuel efficiency I should anyhow... I'd like to have these old ones rebuilt and ready to go so that I will have them on hand in 32 years when these ones go out on me... yeah that does sound ridiculous, so no hurry... actually, they should probably be swapped out every now and then for replacement of fuel line and cleaning?

Ok, time to start my day... engine work or brakes first? hmm...

Ran the cheaper Auto Zone injectors in the '76 that I had for a year or so.
Do not have the same look as the Bosch injectors (shorter) but worked GREAT and pluged right in.
Also had the crimped on injector hoses so there was 1 less clamp I had to worry about.
Make sure your injector seals are in good shape.
Put the cheap ones on and send the OEM ones out for rebuild.
I still have a set of injectors and rails and metal feed lines / cross over lines I could make you a deal on if you need them to send out.
I also have an extra enrichment valve or 2 ( I believe these I tested to be good.)
I also have a TS2 switch or 2 as well.
If your injector seals are cracked they will cause a vacuume leak and you will not run right. (could be your problem...)
You have to order seals for the new injectors if you go this route in that they do not come with seals.
Good luck,
KC

I don't order cheap anything... ever... it's usually not worth it... I may shop around for a good deal, but will not settle for cheap quality. My injectors came with the seals... my old ones didn't have a single crack. The new ones honestly are a denser rubber, so I figure they will probably crack sooner than these, but who knows. I put them on anyway.

I didn't know that Autozone had injectors for our buses... they certainly are cheap! How long have you used yours? For that price its not even worth it to send the old ones of to be rebuilt! Just wonder how good they are...

Let me know what FI stuff you have and what you want for it if you want to get rid of it... I have been trying to get a complete extra set of everything... I would like to have another complete engine ready to bolt in... just in case!

I used these injectors for about 13 months or 6K miles with no problems. I believe they come with a warranty and were available overnight at my local podunk store in Varnel Ga.
I really was surprised how well they worked, the injector tip is about 1/8" shorter than the Bosch OEM ones - I thought it would cause the gas to not vaporize as well as OEM, but they ran great.

I'll check t see if I have any thing else, but I think that is about it.
I'll take $25 for the injectors rails and such that I have.
My '76 didn't have all the extra steel lines going from the fuel rail to enrichment to fuel rail, and from the pump to the 1st fuel rail or fuel rail to regulator.
So, I found all this (injectors still attached) just in case I ever found anothe bus that was Pre '77. Having these would have saved me alot of $ as I replaced all these areas with the 7mm FI hose as OEM. I needed like 3 meters of the stuff (I think it was 11 ft.) That stuff ain't cheep.
Also, now that I have driven my '70 a thousand miles, the power difference isn't something I cannot live without, so all my busses from now on will be T-1 powered...
Let me know,
KC

wait, i'm confused... you have early stuff or late stuff?? Mine is a 78...

running better now?

I used to have a '76 and purchased the extra FI stuff as a spare for it or another pre-77 FI bus (lack of metal lines hurts wallet when replacing FI hose...)

I now have a '70 westy that is powered by a T1 beetle engine. It runs great so I never see me using the FI stuff again.
So the gist is I have FI parts for sale - $25.
I know I have
4 injectors
2 fuel rails
2 metal fuel lines to the enrichment valve
1 enrichment valve ( I think I have 2.)
1 TS2 Switch ( I think I have 2.)
-I also think that I have the tank to Fuel rail lines in steel (up to '76 were rubber...)
-I also think that I have the fuel rail to pressure regulator in metal( see above about rubber...)

Any way that is my story of the Bay windows of my life.
I have my '70 for sale, if I sale it I have a '68 that I will build....
So I am not going to use the FI stuff.
KC- out.

You have the long metal line that runs across the back wall above the trans??????!!??!?!?! Cause I really need that one...

I will certainly buy the stuff from you... you know I don't live in Rossville anymore right? We can meet up some time or I can paypal you to ship it or mail you a check or whatever... but sounds like you've got what I need! So I will take it!

I guess the bus is running better... it sounds great, but didn't drive it today cause I was working on my brakes... had to order new calipers My new fav parts store could only get new at $275 a side *ouch* so I ordered them from oreilly's rebuilt with a lifetime warranty for $90 for the pair... don't know why i bought the stupid rebuild kit if the calipers were that cheap! I guess last time i had these rebuilt it cost me like $100 a side or something... I don't know... but the stupid piston wouldn't come out and the dust boot wouldn't go on and I wasted a good 4 hours of my day on these!

I think the bus will be fine. I cannot wait until I am done with school so I can spend more time maintaining my cars!

ASBug wrote:Ran the cheaper Auto Zone injectors in the '76 that I had for a year or so.

I found out the hard way that Autozone no longer stocks that injector. They have one in their entire invetory so they won't take it off the website. I ordered 4 and they waited over a week to tell me that their vendor doesn't even make it anymore. I got finally ordered my rebuilts from busdepot.com

peregrine67 wrote:

ASBug wrote:Ran the cheaper Auto Zone injectors in the '76 that I had for a year or so.

I found out the hard way that Autozone no longer stocks that injector. They have one in their entire invetory so they won't take it off the website. I ordered 4 and they waited over a week to tell me that their vendor doesn't even make it anymore. I got finally ordered my rebuilts from busdepot.com

Well,
That just sucks.
Good luck then with the rebuilds.
KC

so what are we doing about these parts? i'm leaving tomorrow wont have cell phone/computer access til sun

I'm moving to a new house every evening this week / weekend.
It'll be a week or so before I can meet you.
Let me pull them out over the weekend and see if I think that they will ship easily...
KC

I'm in no hurry for them... I live in Marietta now, so it is harder to meet up with you! I can send you money if you want to hold them for me if you don't think they will ship well. Just let me know! Thanks!


BTW... The bus seems to be running great! Can't wait to take her camping again tomorrow...

The stupid new, new, new caliper seems to be sticking slightly too... but the new new new new one won't be here til after i leave tomorrow long story for another time... i'm off to bed for now