Possible fuel line contamination?

I have a problem that needs some consultation. My very low mileage '88 cargo van (5-speed with 4Y engine) was running almost daily for the past year without incident, until a recent oil change, where the valve cover gasket was found to have a leak that required its replacement. (no prior oil leak had been detected at its parking spot)

Abruptly, the engine also began to misfire intermittantly, apparently on one cylinder, with "check engine" light on (also intermittently). After replacing the gasket, analogous symptoms persist: normal idle, but intermittant rough running, with brief (<1 sec) power drops at intermediate engine rpm's, without further warning lights so far.

Previous discussions on this site have noted a problem with rust particles forming, likely in the fuel tank, becoming dislodged, and migrating to the fuel injectors. This blocked their screens, disrupted fuel flow, and generated symptoms like those noted above.

Questions:

1) What other problems give similar symptoms?
2) How long does it take, approximately, and how much engine disassembly is requried, to clean injector screens (and replace the fuel filter)?
3) If there is rust forming in the fuel tank, does the injector problem simply reoccur regularly, till the tank is cleaned out, presumably followed by coating the tank with rust preventing polymer?

Maurice

If you do have rust in the fuel tank check out this link on using Vinegar to clean the tank.http://www.jockeyjournal.com/forum/s...hlight=vinegar
If it is rust you are going to want to flush the fuel line and fuel rail as well as change the fuel filter.
If it is rust just replacing the injector filters wont do it, the injectors will need to be cleaned. Something as small as a hair can began to clog a fuel injector. Attachment 1965

Hi Maurice,

It's true that rough running can be caused by clogged injector(s), but since you're also seeing a CEL, I would lean towards your problem being something else (a clogged injector will not trigger the CEL). These vans have a self diagnostic feature built into the ECU, so anytime you get a CEL you should CHECK CODES. Since the rough running corresponded with a CEL, I would think the two are related, so please check & report back with your code findings.

In order to replace a VC gasket there's a lot of things that need to be disconnected. It's easy to miss one or more connection when putting back together. If one or more sensor connectors were damaged or left disconnected, this can also create the type of issue you are experiencing. Tim

PS: Labor required to disassemble engine enough to remove injectors, then put back together is about 6 hrs. If everything goes right (gaskets separate nicely, no broken hoses or other parts) it's conceivable for the job to be done in 4 hrs, but I would plan for 6 hrs minimum. If passenger seat & engine access cover are already removed, fuel filter will take approximately 15 minutes to replace. It's removal is outlined in THIS POST.

Hello again and thanks for the helpful suggestions.

A. Response to Suggestions: People here have already reported problems with rust particles developing and getting into the injectors, where (Tim says) they require an expensive 4-6 hr engine disassembly to clear out, with a possible need for major repair of the injectors as well (from Dr Injector).

In that context it seems important to determine (a) how common rust formation is in our 25+ year old gas tanks, (b) how to detect it before it sheds particles into the fuel line, and (c) what maintenance would block/prevent (rather than cure) eventual rust damage to the injectors. (Sounds almost like atherosclerosis and embolisms in humans)

A suggestion was offered to use vinegar (5% acetic acid) treatment to remove rust chemically, with a response that such a treatment would be unlikely to clean real rust deposits down to bare metal, and could just lift off any polymer film (or equivalent) installed to prevent rust. Bare metal should definitely rust badly over 20+ years, so there must be a protective film preventing that (as in canned food, and the paint on the outer surface) so rust formation would mean that film has deteriorated, exposing the metal.

So, does anyone have knowledge about the frequency of rust deposits forming in Van fuel tanks, or how to find out when you have them? I know there are better rust solvents than vinegar (think CLR, a phosphoric acid based formula) that can really strip surface rust almost to bare metal in an overnight soak. Supposedly there are also commercial formulas for polymer (?) coatings to use (like paint on the exterior) to recoat cleaned surfaces of fuel tanks to prevent rust.

B. Update: First impressions of engine problems can be misleading, and (as Tim noted) my Van's symptoms did not adhere strictly to the 'fuel blockage' hypothesis. Since I needed food and other supplies, I gingerly drove the vehicle to town along country roads (15 min in 3rd & 4th gears) with some trepidation as the vehicle lurched/hesitated and the engine warning light repeated flashed, but then the engine gradually smoothed out and drove normally through town, and then back.

While there was apparently some kind of blockage in the fuel line, it does not now appear to have been anything as permanent as a mass of rust particles. I will continue to report any changes, but now find the circumstances either mysterious or suspicious.

Maurice

Wow, you must be a doctor or work in the medical field :). Rusty tanks and fuel systems are usually the result of long term storage. The best way to avoid this is to regularly fill the tank and use the gas. It's been my experience that fuel pumps will typically no longer work after such an event, & that requires tank removal to replace. While replacing the pump, one can't help but notice the condition of these internal parts (as shown on page 2 of this thread: http://www.toyotavantech.com/forum/s...ge-not-working). That thread also shows what I've done to improve the fuel filtration. In your situation the 1st thing you should do is check codes & report back. I'm thinking you may have a failed temperature sensor (the one for the ECU) or perhaps a bad o2 sensor and/or failing TPS. Checking codes should point you in the right direction. Tim

Hello again:

Given the puzzling circumstances, I should explain the sequence of events more explicitly. The engine had been functioning without noticeable problems for months, but was approaching time for an oil change. The change was done at a 'quick oil change' garage along I-5. At that time the service personnel mentioned there was an oil leak that would require a new valve cover gasket, and suggested a nearby garage where they mentioned they had an ongoing relationship, with numerous referrals. There had previously been no oil leak noted at the vehicle's parking spot.

On the short distance (5 min) drive to the suggested garage the engine began to run very roughly, with intermittent misfires on one cylinder, and the 'check engine' light flashing on and off. At the suggested garage, the gasket was changed, but I was told the engine would need extensive tests to determine the cause of the other problem. Despite this nonchalance about the engine misfiring etc, they did suggest an extended list of routine maintenance jobs that added up to around $800.

I declined the suggested jobs, but on the next days drove the vehicle for over 30 min on country roads, during which all irregularity in motor function gradually subsided, leaving the engine performance essentially like it was before the oil change. Under these circumstances it seems unlikely the engine 'malfunction' resulted from some event during the replacement of the valve cover gasket, since it began before that was attempted. Is there any familiar 'natural' circumstance that could explain this curious sequence of events?

Check codes already?

With assistance from an experienced mechanic, the ECU delivers one signal only, a #14 (no "IGF" signal to ECU 4-5 times in succession) indicating a problem in the igniter or ignition coil/circuit. Does that dictate a particular solution, or is further testing required?

Based upon the discussion thread of a similar code 14 problem, which also involved intermittent misfiring, the problem turned out to be a defective "igniter." Is that a single part, still the most likely option, and where are they available these days?

Could such a failure be triggered by something as simple as an oil change?

4 things can trigger that code. Here they are in order of most likely to least likely:

1. Faulty ignition coil

2. Faulty igniter

3. Faulty ECU

4. Faulty wires or connections associated with any of the above

This code can also be triggered by a tech cranking the van with an ignition component disconnected. Normally when this code is discovered I would advise to clear codes, then drive to see if it comes back (chances are it won't). However, in your situation, since you had a blinking CEL at the time the van was sputtering/acting up, I would tend to believe your problem is directly related. Obviously it's intermittent or the van would not run at all. Since it's intermittent (hard to determine cause), and since coils are readily available at a reasonable cost (AM around $40), and because it's also the most likely cause, I'd start by replacing that. Note: This is a common coil and was used in all vans 84 - 85..........Many other models use this same coil.

If problem reoccurs and same code comes back, I'd change the igniter next. Note: New igniters are very expensive (around $500), but last I checked they were still available (same one was used in all vans from 86 - 89, but this is a van specific part & is only available through Toyota). Up til about a year ago we could find used ones on eBay for $50 - $100, but I haven't seen any on there since. When vans are in my local pick-n-pull, I can usually buy these between $5 - $20 (just depends on who's working the til). If I'm making a large purchase they will often just let me have for free.

If your problem still reoccurs (not likely), I might try swapping ECUs. The best way to get one is to get the Toyota part number off your old one (printed right on it) then do an eBay search for a used one. At any given time there are usually 2 or 3 of each year/flavor of ECU for around $50 - $100. Tim

Thanks Tim for your advice. Since earlier threads also noted the Code 14, I was aware of the list of issues to consider, and will have the ignition coil swapped with a replacement asap.

I also did some looking online for the "igniter" and found possible variations in the name of the part, with aftermarket suppliers claiming to have similar (igniter) parts compatible with Toyota Vanwagons (also pricey, but as low as $150, much less than Toyota). These are variously called "ignition control modules," "ignition control units" and other names (than "igniters").

See examples:-

http://www.oreillyauto.com/site/c/se...Van&vi=1279818

http://www.jcwhitney.com/msd-ignitio...6y1988g980u0j1

So, until the coil swap results are in, I have tentative questions:-

1) Are the above noted parts equivalent to a Toyota Van "igniter," as claimed?
2) Will driving the Van to acquire parts (or other things) further damage the vehicle?
3) Could actual damage to the electrical control (computer) circuits (as opposed to just activating a code in the ECU) accidentally have been caused by mistakes made by techs doing an oil change, while trying to assess damage to the valve cover gasket? That would explain the remarkable onset of the problem, immediately after the oil change.

The ones in the 1st link look like they would actually interchange (I didn't think aftermarket igniters were available). However, these are almost as expensive as Toyota. Did you notice one says "unavailable" and the other 2 say "call for availability"? I don't believe the thing in the 2nd link will do the job, but don't know for sure. Looks kind of big........where would you put it?

I don't believe driving like this would hurt anything............except maybe your feet (if you end up walking home) :bdmd:. Maybe the oil change guys did something, maybe not. Seems to me more likely a coincidence (but who knows). Tim

For assistance I downloaded the '87 service manual you noted, but also found comments that there were changes in the electrical system in 88-89 models. Do you know where I could download service manual for those years?

That 87 service manual on PDF is a bootleg copy somebody did without permission from Toyota. Considering the work it took I'm a bit surprised it even exists. Over the years it's been shuffled around the internet & a lot of people have downloaded it, so it will likely be around for a long time. To my knowledge there are no other Toyota Van manuals in PDF format. 86 & 87 vans are pretty much the same & the changes on the other years are are few. The 87 manual works for 95% of van related issues. 88 - 89 vary from 87 only in some small ways (electrically). There are more differences for 84 - 85 vans.

If you don't have a paper service manual for your van I recommend getting one. There's not any 88 manuals on eBay right now, but there's (1) 89 manual. I don't believe there were any changes between 88 - 89, so this should work: http://www.ebay.com/itm/1989-Toyota-...716eb2&vxp=mtr

You previously noted:-
----------------------------------------------------------------------
"4 things can trigger that code (14). Here they are in order of most likely to least likely:

1. Faulty ignition coil

2. Faulty igniter

3. Faulty ECU

4. Faulty wires or connections associated with any of the above"
--------------------------------------------------------------------------------
Since the vehicle was previously running without issue, I presume the correct diagnostic procedure is first to change just the ignition coil, then test drive to see whether problem is gone. If not, then move on to change the "igniter" (or ignition control module) etc.

Alternatively, one could also change other parts, as in a conventional "tune up" along with the ignition coil?

While troubleshooting variables are your enemy. IMO it's best to limit variables as much as possible until the core issue is resolved. What if you make multiple changes and a new part is defective? What if you make a mistake & create another issue?

When it comes to intermittent problems, I personally like to know what the problem was (helps refine my troubleshooting skills). For this reason I typically will only change one thing at a time. This is just me though & I can go overboard at times. It probably doesn't matter that much though so do what you think is best. Every mechanic has his methods & not all agree with mine. Tim

Aftermarket parts are available locally for conventional tune up items, but are these valid substitutes for the van? See:-

http://www.oreillyauto.com/site/c/se...Van&vi=1279818

http://www.oreillyauto.com/site/c/se...Van&vi=1279818

Also:

I had problems with a dirty throttle body on a trip out-of-country, where the locals were unfamiliar with cleaning the unit. Tim has an extended article on cleaning them, but that sounds like an expensive job if you need to pay someone else to do it, particularly if they don't know how, and time is short.

Used throttle bodies are available just now on eBay for around $50 (plus shipping), which seems inexpensive compared to paying for cleaning one. Do you think it advisable to acquire such a (supposedly) clean used part as a backup, when it comes to market?

Some AM stuff might be okay but some is junk. Fuel filters and PCV valves are probably fine using AM. For spark plugs I'd get the Denso P16R. Here's a good deal: http://www.ebay.com/itm/361009603769...%3AMEBIDX%3AIT (I just bought a 10 pack of these).

For dist cap, rotor, plug wires. I personally prefer to pay the higher Toyota price as OEM lasts a very long time. If there's clean looking throttle bodies on eBay I'm guessing they've just been sprayed down with a spray can of cleaner. That might make them look pretty, but won't clean inside the passage ways like a good soaking will. Best to take it apart and do it right. I tell you what, send me your dirty TB & I'll tear it down, clean it up, put a new TPS on it and adjust (you pay return shipping). For my time, chemicals, butterfly screws, and the new TPS I'll charge a flat fee of $150. If you're interested PM me to work out details. Tim

BTW, a couple used igniters showed up on eBay. They are spendy (both around $100). Here's the links:

http://www.ebay.com/itm/231354941557...%3AMEBIDX%3AIT

http://www.ebay.com/itm/231354940414...%3AMEBIDX%3AIT