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Post by turbdo88 on Oct 7, 2017 18:38:40 GMT -5
So from a few other problems my Afr started to read leaner after finding melted hollow magnaflow cat after traveling across country when I noticed my new 3 inch down pipe to 2.5 tail pipes were touching fuel tank and cause to boil . I puttered of hi way to gas station and when I took had cap of it gurgled for about three min no exaceration. I moved pipes of tank and fixed that right on spot. . Well I gutted the cat next day when posted problems here and stinger said sounded like a plugged cat. It was... Its all better but I noticed a little pinging and not the power it had. Well my question is by putting the new magnaflow cat back on would that possibly show a richer reading at full throotle .. I use to see hi elevrns low twelve. Now I see mid twelves. Any ideas I been over everything else.
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Post by Stinger on Oct 7, 2017 22:10:52 GMT -5
If it restricts power then it will richen the AFR with the stock ECU. Raising base fuel pressure a bit is a better option to richen it a bit.
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Post by turbdo88 on Oct 8, 2017 18:06:54 GMT -5
Well I already got the new cat from you so I will put back in this weekend and see what it does. I do have a adjustable FPR but really didn't want to put it in until I maxed out fuel and needed it. with everything being stock except your three inch dual exhaust and knn ,HP walbro 255 pump and boostvalve set at 18lbs timing at 10 , plugs gapped at 28, i shouldn't need adjustable FPR right?
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Post by Stinger on Oct 8, 2017 21:51:07 GMT -5
Running lean in boost is the definition of "maxed out fuel". The whole point of an adjustable FPR is to fix that problem by getting you a little more fuel flow.
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Post by turbdo88 on Oct 9, 2017 17:35:56 GMT -5
Yes I totally understand that about fuel . It's just that before the exhaust causing problems I use to see hi elevens under full boost. And it ran absolutely perfect . Lots of power and torque. Now it seems to have a slight ping under full boost and it's leaner according to wideband. And doesn't seem to have the power it did .I did go over everything ,even checked compression.evertthing seems perfect. I jusr don't want to ad fpr to make up for a issue. I mean generally with my mods I shouldn't need to add more fuel should I. Shouldn't computer adapt pretty well still .
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Post by Stinger on Oct 9, 2017 23:05:03 GMT -5
The stock computer doesn't adapt to anything at WOT. O2 sensor is ignored, VAM is maxed out by 4000 rpm on a bone stock engine which means there is NO adjusting going on when mods are added. The only thing that allows "some" mods is that it's very rich in stock form (low 10's) so mods will lean it out until it's "too lean" like you're seeing.
Airflow restriction from cat = less fuel demand because it's restricting airflow/power.
Remove cat, it's too lean (more airflow than fuel flow), lean condition causes pinging and makes less power.
Adding fuel pressure will bring fuel flow up to match airflow which will richen the AFR, eliminate pinging, and bring power back.
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Post by turbdo88 on Oct 11, 2017 15:37:06 GMT -5
You couldn't of said it any better t.y
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Post by turbdo88 on Oct 11, 2017 17:34:51 GMT -5
With that being said , what is your opinion on the vam mod on turbo Ford site. I done this mods years ago and it happened to be on a 88 turbo coupe that happened to be the best running car I ever had . It was faster than two other turbo coupe I had at time .. (and both quarter panels were banged up) Not a hiccup or stumble ever once in that car. It was the car that got me so obsessed with the 2.3 turbo.. Although I hit a tree due to ice. Car is long gone. The car use to idle so smooth you could barely tell it was running, if you put hand on intercooler it was so smooth you couldn't even feel vibration. The weird thing with that car was I had the vacuum line going to intercooler with a t and the other going to map sensor. If I deleted vacuum to map it would have that slight hiccup . I know it's wrong but I ran it like that for years.. I had two at same time and could never get any to run Like that car did. I swapped almost every part of that car and put in other cars (to get power and smooth idle ) ,. And nothing ever worked. I always ended up putting parts back on cause nothing ever made the other cars run like the one did. Anyhow what is the benefits of vam mod in your opinion , is there , t.y
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Post by Stinger on Oct 12, 2017 0:10:14 GMT -5
My opinion is it's something people did when there were no good methods to tune these engines. It throws off the ECU's load calculations which throws off timing advance since it's not calibrated as Ford intended. Adding spring tension also restricts flow through the intake since the spring is pushing harder against the incoming air. With that said, if you decide to do it, mark where it was before you messed with it so you can revert back if necessary.
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Post by turbdo88 on Dec 12, 2017 21:20:08 GMT -5
So I forgot to mention at cruise all speeds I see 15.5 to 15 Afr. Once in a while I am seen 10,5 at full boost. But usually 11.5 to 12. I do have a very small exhaust leak were pipe connects to elbow of of turbo.. but either way I feel the Afr is accurate in reading. Cause if I rev it slowly in neutral it it slowly richens for a sec them goes right back to 15 to 15.5. So I feel like the leak would cause it to be a big difference in change at 1000 rpm vs 3000. But it doesn't .. so I assuming gauge is giving right readings.
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Post by Stinger on Dec 12, 2017 22:47:08 GMT -5
Commanded AFR at idle and 3000 rpm and low load (neutral) is the same (14.7).
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Post by turbdo88 on Dec 12, 2017 22:54:07 GMT -5
It's driving me crazy this slight pinging at full boost 17 psi with a completely stock turbo coupe with 3 inch dual exhaust ,magmadlow mufflers , 255 walbro HP pump. Gilis valve , k n cone filter on vane. I just can't see how I can be running out of fuel at this point. I haven't put hi flow cat back on yet cause i crushes pipes with clamps and am not ready to mess with fighting it of yet. It definitely sounds like a marble in a can. It's very minimal. Sometimes worst than other . It does tend to get worst if I put premium switch on premium. I do run 93. And have been using Lucas fuel stabilizer lately. But that done seem to help either. Anything else I can check that crosses your mind. Thanks again
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Post by Stinger on Dec 13, 2017 0:25:55 GMT -5
From the factory they have timing for stock compression, 15psi, no oil contamination, etc. Basically it's a best case scenario.
In your case you're running more boost (but not less timing), you've got an old engine that likely has carbon deposited on the pistons (higher than stock compression), you're likely getting some oil contamination in the chamber from PCV or turbo, and you're feeding it with hotter air temps since more boost=more heat (unless you've got an FMIC).
You're basically saying it's not possible that it's detonating but yet say it is, and say it gets worse when you have it in premium mode (which adds timing). So if you want it to go away, pull some timing, or pull some boost, or lower charge temp, or prevent oil contamination, or make sure it's not out of fuel, etc.
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Post by turbdo88 on Dec 13, 2017 2:33:02 GMT -5
It's been really cold her in 30s.. I can say the intercooler is cold to the touch after a drive. I also do have a blanket on turbo with dramatically reduced heat under hood I noticed. I never had a oil problem.or ever noticed low oil even after a few thousand miles . I I never get blow by of any sort. Plugs look perfect Everytime I check them .car only has 78000 mules and always been garaged and taken very good care of. This car ran absolutely perfect before I had overheated fuel and engine on a trip to Colorado. Nothing has changed except a gutted cat. I did put a cheapo advanced auto parts fpr on there before u figured cat was melted. mabye I should swap it out? I will put the cat on this week sometime and if everything is right it should be back to normal.n o more pinging..Afr should show 10.5 full boost and 14 5 ish at idle like it did. I already did pull boost by the way since all this .. I was runnin 17.5 I now have it around 16. I jusr don't see how cat vs no cat can change Afr and run me out of fuel to a point of pinging with less boost
.I just feel something else is wrong I am missing.. I just don't want to put the Kiran fpr I got on and ad more fuel to cover a problem. (Until I get it running like it did ) I will post back after I put cat back on .. As and any idea about my wideband ..why would it be reading 15.5 to 15 at idle and cruise. Cause again before it read 14.5 to 14.7. unless it wrong . But I don't think so. Thanks v again for all your help . Sorry if I seen persistent .I really appreciate the advice
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Post by wesk on Dec 13, 2017 15:02:57 GMT -5
Because removing the CAT increases engine VE. Increasing engine VE means it will be leaner at the same point. These cars were out of injector STOCK.
The ECU constantly attempts to target 14.7 at low load conditions. It will constantly swing slightly rich, and slightly lean of this number. 15:1 is not that different, considering its a different sensor at a different location (than the factory narroband). Don't worry about what it is doing at light loads and cruise, as it is simply doing what it is going to do. If it read half a point richer before with a clogged cat, that also isn't all that suprising, as the clogged cat will change how fresh air dilutes the measurement stream at low loads.
Are you measuring fuel pressure under boost?
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